But given the delegate deficit that Hillary Clinton has right now in terms of pledge delegates, very important for her to do well here.

NPR: Clinton Confident on Eve of Pa. Primary

Then there is a third class, known as similares, medicines which, drugmakers pledge, have the right amount of active ingredient but aren't tested in the body.

FORBES: Magazine Article

Only John Redwood, a former cabinet minister and a bit of a lone voice on the right, asked for a pledge that Britain would not make further loans to euro-zone members.

ECONOMIST: Bagehot

Conservative lobbyist Grover Norquist, whose Americans for Tax Reform pushes candidates to sign a pledge never to raise taxes, said the plan "right now, as explained" would preserve most of the Bush tax cuts and wouldn't violate his group's pledge.

CNN: STORY HIGHLIGHTS