Rep. Emanuel Cleaver (D-Mo.) warned Sen. Claire McCaskillClaire McCaskillThe DNC in the age of Trump: 5 things the new chairman needs to do A guide to the committees: Senate Juan Williams: Senate GOP begins to push Trump away 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 BluntA guide to the committees: Senate Judiciary Committee wants briefing, documents on Flynn resignation Intel Dem: House GOP now open to investigating Flynn 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 McCainDrug importation won't save dollars or lives Dem rep Charlie Crist files for divorce Why the GOP cannot sweep its Milo scandal under the rug 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 SessionsJeff SessionsGOP lawmaker suggests Sessions should recuse himself from any Russia probes Pelosi calls for DOJ probe of Priebus on FBI, Russia Roger Stone: Marijuana crackdown would be 'huge mistake' 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.”