In New York, for example, Democrats are concerned that should Mr. Paterson remain in the race, he would invite a challenge from Rudolph W. Giuliani, the former mayor of New York who ran for president in 2008 and might again.
The 144 Republicans who voted against the agreement to reopen the government were not all Tea Party activists, but many feared that appearing to side with Democrats could invite a challenge from more conservative rivals during primary elections, especially if they are criticized by activist groups that monitor ideological purity.
Justice Anthony M. Kennedy, in a Supreme Court ruling last month, all but invited a constitutional challenge.
Justice Kennedy invited a fresh challenge to that decision, Quill Corporation v. North Dakota.
Last June, Supreme Court Justice Anthony Kennedy wrote a separate opinion, in a case not even addressing solitary confinement, that invited a constitutional challenge to the practice.
He all but invited a further challenge, and many voting rights specialists say that Congress must act soon to change the law if it is to survive another encounter with the Roberts court.
In the end, Alito left that old precedent in place, but virtually invited a future challenge to it.
A lethal injection procedure became the subject of a U.S. Supreme Court case, prompting one justice to write a dissent that all but invited a constitutional challenge to the practice.
The case was also notable for a dissenting opinion from Justice Stephen Breyer, who all but invited a constitutional challenge to the death penalty itself. .
But anti-abortion legislators in conservative states have been chipping away at abortion rights with law after law, hoping to invite a legal challenge that could eventually advance to the Supreme Court and challenge Roe v. Wade.
