Embattled Missouri Republican Congressman Todd Akin insisted Tuesday he would not pull out of his Senate campaign against Democrat Claire McCaskill.

Akin’s comments about pregnancy and rape have become the fodder for news stories across the political spectrum and across the country. His reluctance comes with a new commercial in which he apologizes for the comments.

U.S. Sen. Roy Blunt, former Senators John Ashcroft, John Danforth, Kit Bond and Jim Talent are asking Akin to drop out of the race. The current and former lawmakers released the following statement:

“We do not believe it serves the national interest for Congressman Akin to stay in the race. The issues at stake are too big, and this election is simply too important. The right decision is to step aside.”

American Crossroads, the Superpac that has already spend hundreds of thousands of dollars for campaign commercials supporting Akin, is now asking Akin to withdraw. Here’s a statement released today by American Crossroads:

“Rep. Akin faces a simple choice: Will he help Democrats hold the McCaskill seat and potentially the Senate majority by staying in the race, or will he help Republicans defeat Barack Obama’s most reliable ally in the Senate by getting out?”

Dr. Jack Willke, founder of National and International Right to Life, offered an open letter on Tuesday:

“I made the opportunity today to talk with Rep. Todd Akin because I was so outraged at how quickly Republican leaders have deserted him. After talking with Rep. Akin, I’m even more outraged.

“Rep. Akin remains a strong and courageous pro-life leader—and awkward wording in one sound-bite doesn’t negate that. His traditional pro-life position to protect every innocent human life has been completely distorted by the national media and even the Republican Party.”

At a campaign event in suburban St Louis, Senator McCaskill said Missourians should be allowed to make a choice “based on policy, not backroom politics.” McCaskill says she’s startled that “party bigwigs are coming down” on Akin.