SurveyUSA looks at the two most likely Republican nominees, alone and paired as a Republican ticket, running against the existing Democratic ticket of Barack Obama and Joe Biden, and a new Democratic ticket of Barack Obama and Hillary Clinton. Here is the progression of match-ups, and the results:

• Obama 31%
• Romney 56%
• Republicans by 25 points.

• Obama 35
• Gingrich 52%
• Republicans by 17 points.

• Democratic ticket of Obama-Biden 32%
• Republican ticket of Romney-Gingrich 56%
• Republicans by 24 points.

• Democratic ticket of Obama-Clinton 34%
• Republican ticket of Romney-Gingrich 56%
• Republicans by 22 points.

• Democratic ticket of Obama-Biden 34%
• Republican ticket of Gingrich-Romney 53%
• Republicans by 19 points.

• Democratic ticket of Obama-Clinton 34%
• Republican ticket of Gingrich-Romney 52%
• Republicans by 18 points.

In 2008, John McCain carried Kansas by 17 points.

Full results and interactive crosstabs here.