Rep. Emanuel Cleaver (D-Mo.) warned Sen. Claire McCaskillClaire McCaskillSenators push for possible FCC enforcement over Lifeline fraud Democrat senator: Trump has elevated Kim Jong-Un to the world stage It's time for McConnell to fight with Trump instead of against him MORE (D-Mo.) of "disloyalty" to President Obama if she should seek to distance herself from the White House in her re-election campaign.

Cleaver, who's seen as the likely next leader of the Congressional Black Caucus (CBC), cautioned the centrist senator of distancing herself from Obama, the way many endangered incumbents had done in the closing weeks of the 2012 election.

“Any attempt to extricate herself from him will be an act of disloyalty,” Cleaver told McClatchy in a piece profiling McCaskill's re-election campaign. “She will not do that at all.”

McCaskill is one of the centrist Democrats who managed victory in the 2006 election thanks to the headwinds favoring her party in that cycle.

Since winning, though, there have been signs that the Show-Me State has trended Republican. Rep. Roy BluntRoy Dean BluntGOP debates tax cuts vs. tax reform Five tough decisions for the GOP on healthcare Lacking White House plan, Senate focuses on infrastructure MORE (R) easily secured victory in the state's Senate race this fall, for instance. And McCaskill might feel justified in running from Obama in 2012, since it was one of the few swing states Sen. John McCainJohn McCainBush biographer: Trump has moved the goalpost for civilized society White House to pressure McConnell on ObamaCare McCain: Trump needs to state difference between bigots and those fighting hate MORE (R-Ariz.) managed to hold onto the 2008 presidential election, while Obama was sweeping to victory elsewhere.

McCaskill has sided with the president and majority Democrats on a series of key votes. She voted for healthcare reform, Wall Street reform and the stimulus bill.

But on other issues, she's sought to assemble a maverick record. She led the (successful) effort to do away with the Senate's longtime practice of allowing members to place anonymous holds on presidential nominees. She has joined with Sen. Jeff SessionsJefferson (Jeff) SessionsFBI opens tip line requesting information on Charlottesville rally Sessions rails against Chicago during visit to Miami DOJ warrant of Trump resistance site triggers alarm MORE (R-Ala.) to push for legislation capping discretionary spending. And she's also long favored earmark reform, an effort to which Obama lent his support in his weekly radio address on Saturday.

“Earmark reform has been a lonely fight for a long time, so it’s encouraging to have others taking this issue seriously, especially among Democrats since I will be the only senator from my party opposing earmarks after the new year,” McCaskill said Saturday in a statement. “The bottom line is that tax dollars shouldn’t be doled out based on politics or secret deals, and it’s time both Democrats and Republicans join together to stop them.”