The following table is, simply, a compilation of those Election Years in which States (or equivalent jurisdictions) were permitted to use the Direct Primary (a Primary Election, as opposed to the indirect Primary [that which we, nowadays, would call either Caucuses or Mass Meetings]) to nominate candidates for Statewide and/or Federal elective office under either specific statutory provisions providing for same or (albeit far less commonly) constitutional provisions authorizing the State to adopt such statutory provisions by law. However, the fact that a given Election Year falls within the periods indicated on this table does not necessarily mean a Primary for a nomination was necessarily held that particular year (in fact, in certain such cases, exceptions and other anomalies are noted- alphabetically by State or equivalent jurisdiction- directly underneath this table); in addition, a Direct Primary was not necessarily held re: nominations in both Major Parties in any given Election Year (this was especially true in the solidly Democratic South going into the 1970s where, as a result, only Democratic Primaries were held in most Election Years).

The Direct Primary (as a replacement for the older Caucus/Convention system of Party nomination for elective office) actually dates back to at least just after the Civil War (in a few counties in Pennsylvania: some historians have been able to identify usage of a Direct Primary even before the Civil War); what we would now merely term a Primary Election was utilized in a few counties in neighboring Ohio- and then Indiana- not long after its first widespread use in Pennsylvania-- but it was in Midwestern and Western States (most notably: California, Colorado, Iowa, Kansas, Nebraska, Nevada, South Dakota, Utah and Wyoming) that local county political organizations (affiliated with one, if not both, of the two Major Parties) began to adopt it (it should be made most clear that the Direct Primary was decidedly local and not at all Statewide in its usage in these States). Colorado and Nevada first adopted mandatory Statewide regulations of these Direct Primaries in the 1880s (Iowa would join these in this regard in the late 1890s) but these regulations were not applied throughout the State (that is: the old Caucus/Convention was still permitted by local- more usually, county- option) and said regulations did not at all contemplate candidates for State office (or, for that matter, Congress) being nominated by the voters per se. The other States so named in this paragraph would follow the lead of the first three States shortly after the Turn of the Last Century (indeed, come 1905, only South Dakota- among the 9 States named herein- had no mandatory Statewide regulations of any local [again, almost always countywide] Direct Primaries).

By the 1880s, the Direct Primary had already spread to the South and it was to be this region (primarily because of the local dominance of the Democratic Party once Reconstruction had come to an end) that would take the lead in applying it to State and Congressional nominations- as opposed to merely those for county and other more local offices- principally because the Democratic nomination for office, at just about every level of governance, was almost always tantamount to election: South Carolina was the first State to adopt Statewide mandatory regulations that included nominations for elective State and Federal office (in 1888: keep in mind that, at this time, United States Senators were still being chosen by State legislatures and, therefore, would not be subjected to the Direct Primary) but left it up to each Party to decide whether or not (as well as at what levels) to actually use it (in practice, as already implied, Direct Primaries were far more usually utilized by Democrats back then)-- this tended to be the pattern that prevailed amongst the former members of the old Confederacy (as well as several of the so-called "Border South" States in which Democrats tended to at least generally have the upper hand, politically, over the Republicans during this period) up to- as well as through- the Turn of the Last Century (by 1900, North Carolina was the only State south of either the Mason/Dixon line or the Ohio River without any such mandatory regulations applying even to Direct Primaries used for nominations to State or Federal office). Thus, by the first few years of the 20th Century, the key difference between the Direct Primary States of the Midwest and West and those in the South was the seeming lack of use of the Direct Primary for State/Federal nominations outside the South.

South Carolina also led the way in adopting specific statutory provisions regulating the Direct Primary in that State (under a provision in its new Constitution of 1895: thus, South Carolina had statutorily regulated Primary Elections on the books in time for its 1896 elections) but it still remained optional in that State (as would also remain the case in both Mississippi and Alabama, which followed South Carolina's lead in this regard in the first few years of the new Century, as noted in the table below). As a result, Wisconsin- followed quickly by Oregon- do, in fact, earn their rightful places in American History for being the first States to require mandatory Direct Primaries- re: nominations for elective office by both Major Parties- throughout the entire ballot (said requirements first taking effect for elections in 1904, as noted in the table below); it was to be the observed experiences in these pioneer States that would, as the table itself indicates, lead to the spread of the Direct Primary throughout most of the country by the end of the 19-teens (by 1920, only 5 of the then-48 States [Connecticut, Delaware, New Mexico, Rhode Island and Utah] had no statutory provisions at all for Major Party nomination for either Statewide or Federal elective office by Primary Election).

A Note about RUNOFF ELECTIONS: A runoff election is a second balloting held some time after the first Direct Primary where no candidate in that first Primary Election has reached a particular threshold (usually, but not necessarily, a majority of the total votes cast in the original Primary): the resultant runoff is held between only the two candidates for nomination with the highest number of votes in the first Primary (thereby guaranteeing that the victor will have a majority of the Runoff vote). The Runoff was- and remains- most prevalent in the South (despite the fact that the Republicans are now the more dominant Party in that region [though the Democrats in the South are, nowadays, certainly not as marginalized, politically, as were the Republicans of the same region a century or more ago!]) and, again, this all goes back to the days when the Democratic Party was the predominant Party in the region (since the Democratic nomination was- for all intents and purposes- the "real Election" [leaving the General Election to come a mere formality], having a nominee of that Party who had won the majority of the vote in at least one Direct Primary- the Runoff, if not the first Primary- was most desirable throughout most of the South [only Tennessee, among the members of the old Confederacy, has never utilized the Runoff- although Virginia, as can be seen from the table below, used it only very briefly]).

Prior to adopting the Runoff, a very few Southern States utilized so-called "Preferential Balloting" in their Direct Primaries (FLORIDA used this system before first adopting the Runoff after the 1928 elections; in addition, both ALABAMA and LOUISIANA- apparently in an effort to save money by not having to incur the expense of a second "Runoff" election- actually abandoned the Runoff in favor of such "Preferential Balloting" after the 1914 elections, only to return to the more usual Runoff after the 1930 elections in the case of Alabama and the 1920 elections in the case of Louisiana) . In such "Preferential Balloting", the voter is specifically permitted to vote for more than one candidate for nomination to a particular office by indicating which candidate is his first choice, second choice, etc. (though the more usual practice in the three Southern States that used this process was to limit the voter to only two such choices, however: thus, in said States during their usage of "Preferential Balloting", where the number of first choice votes for each candidate did not give any candidate an outright majority, second choice votes for candidates would then be added to these first choice votes for each candidate until one candidate not only emerged with more votes than any other but also ended up with a majority of the total votes cast [thereby- at least hopefully- accomplishing, with but one Primary Election, what the more common additional "Runoff" was itself intended to accomplish]).

Connecticut originally adopted a so-called "challenge primary"- in which a candidate not nominated by a Party Convention held before the scheduled date of the Primary Election could only get on the ballot (and, thereby, face off against the Convention's choice) through "challenge" (having already gained a minimum threshold of the Convention vote: where no such threshold was reached by any challenger, no Primary would be held for nomination to that office)-- thus, there were not necessarily Direct Primaries for Statewide and/or Federal Office (that is: members of Congress) every even-numbered year from 1956 on. Recently, however, Connecticut has now allowed for also getting on the Primary ballot by petition.

Delaware actually originally adopted the Direct Primary in the mid-1920s but nominations for Statewide elective office were still made by Party State Convention through 1970 (since Delaware was never entitled to more than one Representative in Congress throughout the entire period, all Federal elective offices in the State were- by definition- Statewide: thus, there were no Primary Elections- even for Congress- at all during all this time). From 1972 through 1978, Delaware used a nominating system for Statewide office (including its sole member of the U.S. House of Representatives) similar to Connecticut's "challenge primary" above; Delaware began utilizing the mandatory Direct Primary- even for Statewide office- in 1980.

Louisiana, in 1975, began using- but only for its State elections (it did not originally apply to nominations to Federal office)- what it called its "Open Primary", in which all candidates for a particular office run against each other "all up"- without regard to Party or even lack of any such political affiliation: where a candidate receives a majority of the total vote in this "Open Primary", that candidate is deemed to have been elected to the office being contested for; where no candidate receives a majority of the vote in this "Open Primary", a "runoff" is held between the two top vote-getters and the winner of any such "runoff" is elected to the office (thus, there are no real 'Party Nominations' per se in this system). In 1978, Louisiana began using this "Open Primary" for nominations to Federal office (United States Senate and U.S. House of Representatives). After two unsuccessful attempts to fight lawsuits maintaining that holding the "runoff" for Federal office (as opposed to the original "Open Primary") on General Election Day in November is illegal (because members of Congress could otherwise be elected before the first Tuesday after the first Monday in November in violation of Federal law), Louisiana- beginning in 2008- returned to its older system of Party nomination by Direct Primary (with a Runoff where no candidate received a majority in the Primary Election) for Federal office only (Louisiana continued to use the "Open Primary" for its State elections, held at a time other than its elections for Federal office).

Utah had (as noted above the table) local Direct Primaries before the Turn of the Last Century and, in the early 1920s, first adopted a State Direct Primary law (the kind political scientists of the time would have referred to as being "of the old type" [in which Statewide regulation of optional local Direct Primaries was merely provided for]): it was not until 1938 that Utah fully implemented mandatory Primary Elections. From 1948 through 1962, Utah utilized the mandatory pre-Primary Convention (in which a Party Convention held prior to the scheduled date of the Primary Election would endorse candidates for each office, although a candidate for nomination coming in second in votes at said Convention would still be able to face the endorsed Party candidate in a Primary: there was no other way to get onto the Primary ballot, however); effective with the 1964 elections, however, Utah adopted what might fairly be called the "reverse" 'challenge primary' (in that a Direct Primary would be held only if the endorsed candidate failed to reach a particular maximum percentage "threshold" of votes at the Convention: said Primary Election- if necessary- would then only be between the two top vote-getters at said Convention). In essence, then, from 1948 on, Utah has been using its Primary Elections as, more or less, a "runoff" in relation to the vote for candidates for nomination at Party Conventions (with a required percentage "threshold" to avoid any such "runoff" only since 1964 [the actual such threshold necessary to avoid facing a Primary challenge having been changed over time since then]).

Virginia, in 1971 (once it had abandoned its brief use of the Primary "Runoff"), began allowing optional Direct Primaries (that is: the Parties themselves decide whether or not to nominate via Primary Election; where they might chose not to, they must nominate by Party Convention [with the proviso that such nominations have already been made by the time the polls have closed on the scheduled date of the Direct Primary]).

• Use of the DIRECT PRIMARY in the several States of the Union since 1912
• Dates of DIRECT PRIMARY Elections re: Major Party Nominations for Statewide and/or Federal Office
• Dates of PRESIDENTIAL PRIMARIES re: selection and/or allocation/distribution of Delegates to Major Party National Conventions