Republicans are frantically trying to get Rep. Todd Akin to drop out of the U.S. Senate race in Missouri after his remark about abortion and rape, but not because it was offensive and ignorant. They’re afraid he might lose and cost them a chance at a Senate majority next year. He would surely be replaced by a Republican who sounds more reasonable but holds similarly extreme views on abortion, immigration, gay rights and the role of government because those are the kinds of candidates the party nominates these days in state after state.

Like many Republicans, including the vice presidential candidate, Paul Ryan, Mr. Akin opposes abortion even when a woman has been raped. But, in an interview that was aired on Sunday, Mr. Akin went further and decided to explain his position by saying that pregnancy rarely results from rape because “if it’s a legitimate rape, the female body has ways to try to shut that whole thing down.”

His comments betray more than a remarkable unfamiliarity with the human reproductive system. They expose a widely held belief among many fierce abortion opponents that a rape exception will be abused by women whose rapes were not “legitimate.” This came up last year, for example, when the Indiana House was debating a stringent abortion restriction and Republicans objected to a rape exception. State Rep. Eric Turner said the exception was a “giant loophole” that could be abused by a woman who falsely claimed she had been raped.

The principal difference between Mr. Akin and most other Republican candidates is that they would be more decorous in inventing reasons to strip women of their abortion rights. One of the two candidates Mr. Akin defeated in the Republican primary last week supported the overturn of Roe v. Wade; the other supported a constitutional amendment saying life begins at conception.

All three positions are outside the mainstream of American opinion, but they are pretty much in the dead center of Republican thinking. Mr. Ryan has said he doesn’t believe in a rape exception when outlawing abortion, and he worked with Mr. Akin in the House in trying to narrow the definition of rape so Medicaid would pay for fewer abortions of poor women. Mitt Romney says he supports a rape exception, but many of the politicians he has invited to speak at next week’s Republican convention disagree with him.

As several recent Republican primaries demonstrated, the party continues to nominate Tea Party candidates who create increasingly ludicrous definitions of “far right.” Ted Cruz, who won the Senate primary in Texas and is all but certain to be elected, favors the closure of the Departments of Energy, Commerce and Education, along with the Transportation Security Administration and, naturally, the I.R.S. He says he is very worried that the United Nations is trying to ban golf courses and paved roads.

Ted Yoho, who won a congressional primary in northern Florida, wants to abolish the income tax and replace it with a sales tax, believes life begins at conception and considers gun ownership a “birthright.”

The Republicans pressuring Mr. Akin to leave the race didn’t seem to care when he said he doubted that Medicare was constitutional or warned that samesex marriage would destroy civilization. If the party wanted to end these kinds of embarrassing moments, it could return to the days when it nominated mainstream candidates.