U.S. Rep. Mark Kirk will not run for the Senate in 2010, the Washington Post’s Chris Cilliza reports.

The North Shore Republican appeared set to enter the race just days ago, after Illinois Attorney General Lisa Madigan announced she would not run.

Kirk had indicated to several state and national Republicans that he would run, including National Republican Senatorial Committee Chairman John Cornyn. One sticking point, the Post reports, may have been Kirk’s vote for President Obama’s climate change bill:

[Kirk's decision] followed a meeting of the Illinois Republican congressional delegation on Thursday in which his colleagues refused to back Kirk in a primary against Illinois Republican Party Chairman Andy McKenna due, in large part, to his vote in favor of President Barack Obama’s climate change bill.

McKenna indicated his plan to run for the Republican nomination earlier this week, though he has not declared.

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