Todd akin
Missouri Rep. Todd Akin may be the black sheep of the Republican Party, but the congressman has refused to drop his bid for the U.S. Senate, despite mounting evidence indicating his campaign is essentially already over. Reuters

Mitt Romney, the presumptive presidential nominee, has added his voice to the chorus of Republicans calling on Missouri Senate candidate Todd Akin to end his campaign.

Rep. Akin has faced a building tsunami of outrage since suggesting on Sunday that women's bodies can prevent pregnancy in cases of "legitimate rape." Several Republican lawmakers have since called on him to step aside and the National Republican Senatorial Committee announced it would no longer spend on his campaign.

Earlier, Romney had stopped short of pushing Akin to resign, releasing a statement saying he disagreed with Akin and noting that under his administration would not oppose abortion in rape cases. But the nominee closed ranks with the party he has been selected to lead on Tuesday, saying in a statement that Akin must exit the race for the good of the party.

"Todd Akin's comments were offensive and wrong and he should very seriously consider what course would be in the best interest of our country," Romney said in a statement. "Today, his fellow Missourians urged him to step aside, and I think he should accept their counsel and exit the Senate race."

Under Missouri law, Akin has until 5 p.m. Central Time (6 p.m. Eastern) on Tuesday to withdraw, after which he would need to obtain a court order to do so. He has so far resisted calls to leave the race and reaffirmed that decision during a Tuesday interview.

Republicans are intent on pushing Akin out because the Senate seat he is seeking, currently held by Democrat Claire McCaskill, is one of their best chances for a pickup. But Akin's rape comment, coming shortly after he triumphed in a Missouri Senate primary, have made him a liability.