Sen. Claire McCaskill (D) called out Missouri's other senator — newly-elected Republican Roy Blunt — on Twitter Tuesday for his stance on earmarks.

Blunt notably came out against earmark-ban proposed by Sen. Jim DeMint (R-S.C.), which has gained traction among incoming conservative freshmen and GOP establishment players alike. 

"Newly elected Sen from #MO is bucking R leadershp by supporting earmarks," McCaskill tweeted, "while I continue to buck mine by fighting."

A spokeswoman for Blunt explained his position to the St. Louis Post-Dispatch using logic once floated by Senate Minority Leader Mitch McConnell.

McConnell, before yesterday, opposed the earmark-ban because it would cede power to the executive branch.

"He [Blunt] thinks it's the prerogative of the legislative branch, not the bureaucrats, to fight for projects in their states after they've sought the lowest possible budget," the spokeswoman said. "If there are state-based projects of significance, he will fight for Missouri's fair share in an open and transparent way."

McCaskill, a longtime proponent of earmark reform, was joined yesterday by fellow Democrat Mark Udall (Colo.) in supporting the ban. 

Lawmakers are continuing to take sides on the issue Tuesday.