For Republicans intent on unraveling President Barack Obama's accomplishments, electing Mitt Romney has been only one part of the equation. Almost as important was installing a Republican majority in the U.S. Senate, where 50 votes (plus the vice president) would be necessary to repeal much of health care reform, roll back tax increases on the rich and gut social welfare programs.

The party's hopes, however, have been severely damaged in recent weeks. Republican candidates who are crucial to regaining a majority in the Senate have tumbled, according to a variety of polls, and Democrats are now considered likely to retain control. The reason for this is clear: Primary voters chose several unappealing or ideologically driven candidates who repelled general-election voters once they began speaking their minds.

In a country facing enormous economic and international challenges, for example, it is stunning that two Midwestern Democrats are leading their races solely because their Republican opponents explained in shocking detail why they oppose a rape exception to a ban on abortion. Neither Richard Mourdock of Indiana nor Rep. Todd Akin of Missouri felt any need to hold back, because their beliefs are central to why they were nominated.

Akin, who is running against Sen. Claire McCaskill, has long opposed abortion in all cases, and, in August, he announced that it was not really an issue because, in cases of "legitimate rape," the female body shuts down the conception process. Mourdock, who is running against Rep. Joe Donnelly, a Democrat, said last month that pregnancy resulting from rape was "something that God intended to happen." Both candidates could still win in their conservative states, but, for now, their insensitive rigidity has left them behind.

In Wisconsin, Rep. Tammy Baldwin, a Democrat, has benefited from the comments of her opponent, former Gov. Tommy Thompson. He said he would come up with programs "to do away with Medicaid and Medicare." Josh Mandel, a Republican who is challenging Sen. Sherrod Brown of Ohio, has a tissue-thin resume and no fixed position on a variety of issues. In Florida, Rep. Connie Mack IV, a Republican who is challenging Sen. Bill Nelson, has been crippled by revelations that he did marketing work on behalf of Hooter's and has a history of barroom brawling and road rage.

Republicans in two relatively liberal northeastern states are fighting a huge Democratic headwind stirred up by the presidential race. Most polls in Massachusetts have shown Sen. Scott Brown either tied with his Democratic challenger, Elizabeth Warren, or behind. (Warren's solid agenda on behalf of consumers and against economic inequality has won her enthusiastic support.) In Connecticut, Linda McMahon's enormously expensive, self-financed Republican campaign has not bought her a lead in the polls against Rep. Christopher Murphy, so now she is committing a laughable party heresy by urging voters to support both her and Obama.

The House is likely to remain in Republican hands, so keeping Democrats in control of the Senate is the best way to fight off savage budget cuts like those endorsed by Romney and Rep. Paul Ryan. That effort has been made a lot easier by Republican Senate candidates displaying their true colors.