THE RIGHT TO CHOOSE.(Robert Casey, Jr., Pennsylvania politics)

As Democrats regrouped after last year's elections, Senator Charles Schumer, of New York, the chairman of the Democratic Senatorial Campaign Committee, took up the task of preventing further Republican gains in 2006. The Democrats' cause had been reduced to forty-five votes in the Senate, the Party's smallest share in more than sixty years; losing just a few additional seats would give Republicans a filibuster-proof majority.

Schumer had to find money for Democratic incumbents whose seats were at risk and to recruit and fund candidates who might be capable of defeating targeted Republicans. Last winter, as he got started, he almost immediately identified the prize he most coveted. "Both on the substance and on the politics," Schumer recalls, "when we sat down and looked at the map we said our No. 1 take-back seat would be Pennsylvania"--the seat now held by the state's junior senator, Rick Santorum. A fiercely partisan religious conservative, Santorum is to the Democrats the very embodiment of the scary right; his aspirations for national office only heighten the allure of defeating him.

Schumer solicited the advice of Edward G. Rendell, the governor of Pennsylvania and the former head of the national Party: "I said, 'Governor, who can beat Santorum? Is he vulnerable, and who can beat him?' "

Rendell had already gamed out the field. "There's only one guy who can beat him," Rendell said, according to Schumer. "But he doesn't want to run, and you guys wouldn't want him even if he did."

"If he could win, why wouldn't we want him?"