President Barack Obama swept into New Jersey on Sunday, asking supporters to summon the enthusiasm they poured into his election last November and deliver a victory for Gov. Jon S. Corzine.
"He's one of the best partners I have in the White House. We work together," Obama said. "We know our work is far from over."
Obama's appearances in Camden and Newark underscored the White House's determination to stave off defeat for Corzine, the only Democratic incumbent up for re-election this year, who is facing an aggressive challenge from Christopher J. Christie, a Republican.
The race is one of several likely to be viewed as a barometer of the president's popularity.
Virginia voters will also choose a new governor on Tuesday, but there, the Republican, Bob McDonnell, has a double-digit lead against the Democrat, Creigh Deeds.
In a congressional race in upstate New York, the White House helped engineer the surprise endorsement of the Democratic candidate, Bill Owens, by state Assemblywoman Dede Scozzafava, the Republican nominee who dropped out on Saturday. The move by Scozzafava, a moderate former small-town mayor, only intensified the intraparty fighting in a contest that has become a battle for the future of the Republican Party.
This handful of off-year political contests offer some clues about how Americans are viewing Obama, as well as an early measure of the landscape for next year's midterm elections.
But precisely what kind of clues?
"These are bellwether races — not just as a referendum on this administration, but on our party as well," said Michael Steele, the chairman of the Republican National Committee.
Joel Benenson, the pollster for Obama and Corzine, dismissed that argument, saying elections were isolated episodes with no long-term political meaning. "I really think this is an obsession of the media," Benenson said. "The reality is that all these elections have very unique dynamics. People read too much into things and try to nationalize races that have local dynamics."
At the very least, the results in the governors' races, if not predictive, are quite likely to drive the political narrative, bolstering or diminishing Obama's political stature as he seeks to rally a divided party. The outcome could, to a limited degree, help measure whether Obama's success last year was a phenomenon limited to him or the early signs of a long-term Democratic resurgence. And it may offer a hint of the thinking of independent voters.