Mitt Romney, who will be officially nominated this week as the Republican nominee for president, appears to trim his social convictions to the party’s prevailing winds. There is no doubt, however, about where the party’s vice-presidential candidate stands. A long history of social extremism makes Paul Ryan an emblem of the Republican tack to the far right.

Mr. Romney’s choice of Mr. Ryan carried some risks, considering Mr. Ryan’s advocacy of overhauling Medicare, but it has sent the strongest signal of solidarity to those who have made the party unrecognizable to moderates. Strident conservatives had been uneasy with Mr. Romney, but it is the rest of the country that should be nervous about conservatives’ now-enthusiastic acceptance of the Republican ticket.

Mr. Ryan is best known as the face of Republican budget-cutting, though his ideology runs much deeper. For years, he has been a reliable vote against workplace equity for women, opposing the Lilly Ledbetter Fair Pay Act, which makes it easier for women to file wage-discrimination lawsuits, and two similar measures.

The full outpouring of hard-right enthusiasm is based, to a large degree, on Mr. Ryan’s sweeping opposition to abortion rights. He has long wanted to ban access to abortion even in the case of rape, the ideology espoused in this year’s Republican platform. (Mr. Romney favors a rape exception.) Mr. Ryan also co-sponsored, along with Representative Todd Akin of Missouri, a bill that would have narrowed the definition of rape to reduce the number of poor women who can get an abortion through Medicaid.