Republicans are frantically trying to get Representative Todd Akin to drop out of the United States 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 Representative 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.