Tuesday 7 February 2012: Missouri Republican non-binding Primary. Today's primary has no effect on delegate allocation.

Missouri Secretary of State: February 2012 Presidential Preference Primary.

Participation in the caucuses is limited Republicans who are registered to vote in that county.

Thursday 15 March - Saturday 24 March 2012: County Caucuses. Participants elect delegates to the Congressional District Conventions and State Convention. The number of delegates per county is determined by the Missouri Republican Party based upon the number of Republican votes cast in the last presidential election.

• There is no formal system applied in the County Caucus to relate the presidential preference of the County Caucus delegates to the election of delegates to the District and State Convention. The delegates in attendance at each caucus alone determine if presidential preference is to be a factor and, if so, how it is to be applied.

Date breakout-- Chariton County: 15 March, Wayne County: 16 March, most counties: 17 March, Jackson County / city of St. Louis: 24 March.

Saturday 21 April 2012: 24 of 52 delegates to the National Convention are elected and bound to Presidential contenders in today's Congressional District Conventions.

Delegates, elected at the County Conventions, meet in each of the state's 8 Congressional Districts. Each District elects 3 National Convention District delegates.

• Before voting begins, the National Convention Delegate candidates indicate their Presidential Preference. The Convention participants then cast ballots for the individual candidates.
• There is no formal system applied in the District Convention to relate the presidential preference of the District Convention delegates to the choice of the district's delegates to the National Republican Convention. The delegates in attendance at each District Convention alone determine if presidential preference is to be a factor and, if so, how it is to be applied.

National Convention delegates are bound on the first ballot unless released by the candidate.

Saturday 2 June 2012: 25 (10 base at-large delegates plus 15 bonus delegates) of 52 delegates to the National Convention are elected and bound to Presidential contenders at today's State Convention. These At-Large delegates are elected by the convention as a whole.

• Before voting begins, the National Convention Delegate candidates indicate their Presidential Preference and organize into slates. The Convention participants then cast ballots for a slate rather than the individual candidates. The slate receiving the most votes, goes to the National Convention.
• There is no formal system applied in the State Convention to relate the presidential preference of the State Convention delegates to the choice of the convention's delegates to the National Republican Convention. The delegates in attendance alone determine if presidential preference is to be a factor and, if so, how it is to be applied.

In addition, 3 party leaders, the National Committeeman, the National Committeewoman, and the chairman of the Missouri's Republican Party, will attend the convention as unpledged delegates by virtue of their position.

National Convention delegates are bound on the first ballot unless released by the candidate.

Notes:

On 6 January 2011, Representative Tony Dugger (Republican) introduced HB 121. This bill would move the Presidential primary from the 1st Tuesday after the 1st Monday in February to the 1st Tuesday after the 1st Monday in March.

HB 503 was introduced on 14 February 2011 and is sponsored by Representative Tony Dugger (Republican). The bill would move the state's Presidential Primary from the first Tuesday after the first Monday in February to "the first Tuesday after the first Monday in March".

16 February 2011: State senator Kevin Engler (Republican) introduced the companion to HB 503: SB 282. Both bills move the Presidential Primary to "the first Tuesday after the first Monday in March". On 16 March 2011, SB 282 was perfected to move the Presidential Primary to "seven days after the presidential primary is conducted in the state of New Hampshire". As of the 4 May 2011 Third Read: a presidential primary ... shall be held on the first Tuesday after the first Monday in March. This bill was vetoed by Governor Jay Nixon (Democratic) on 8 July 2011.

On 28 February 2011, Representative Jay Barnes (Republican) introduced HB 694. This bill would move the Presidential Primary (1st Tuesday in February) and the partisan primary (first Tuesday after the 1st Monday in August) to the 2nd Tuesday after the 1st Monday in June.

On 22 July 2011, Governor Jay Nixon (Democratic) announced that he will ask the General Assembly to pass a bill to move the Presidential Primary from the 1st Tuesday after the first Monday in February to the 1st Tuesday after the 1st Monday in March.

On 6 September 2011, state Representative Tony Dugger (Republican) introduced HB 3 at the 96th General Assembly, 1st Extraordinary Session. The bill would move the state's Presidential Primary from the 1st Tuesday after the 1st Monday in February to the 1st Tuesday after the 1st Monday in March.

On 29 September 2011, the law to move the Presidential Primary 7 February to 6 March 2012 was vetoed by Governor Jeremiah W. "Jay" Nixon and appears to be dead. The Missouri Republican Party will not use the primary to allocate their delegates.

After Jay Nixon vetoed the elections bill and the General Assembly failed to achieve final passage of the presidential primary bill prior to October 1, the Missouri Republican State Committee held an emergency meeting on Thursday to ensure our state is in compliance with the rules of the Republican Party. During this meeting, the committee voted unanimously to amend our call to convention and go to a caucus system for the 2012 election.

11 October 2011 by the Associated Press: Missouri to consider abolishing presidential primary.

On 5 January 2012, HB 1183 was introduced. The bill would cancel the 2012 presidential primary.