The North Shore Republican appeared set to enter the race after Illinois Attorney General Lisa Madigan announced she would not run. A potential sticking point for Kirk, Cilliza reported, is his vote for the administration's climate change bill and a potential primary with state GOP chairman Andy McKenna:
[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.
But Kirk told Roll Call later Friday that he has not made a final decision and is still discussing the race with McKenna. The pair plan to continue discussing the race over the weekend, he said.
The Post's Cilliza has updated his original story to say that while Kirk did tell "several" Republicans that he would not run, "there is an ongoing effort now to convince him to re-think that decision." That effort also reportedly entails convincing McKenna to not run.
McKenna indicated his plan to run for the Republican nomination earlier this week, though he has not declared.