Whether they succeed or fail could affect next year's midterm elections -- when Democrats defend their majorities in the Senate and the House -- and the president's own re-election bid in 2012.
Despite the high stakes, Obama doesn't have much choice but to go to bat for both candidates, political analysts say.
"He's going to be held accountable for the result regardless. He might as well make an effort," Larry Sabato, director for the Center of Politics at the University of Virginia said, adding that if the president campaigns for the Democratic candidates in Virginia and New Jersey, "he's not going to be responsible for their winning even if they win."
Cliff Zukin, a professor of public policy at Rutgers University, agreed.
"If New Jersey goes Republican even if it's by virtue of Chris Christie and statewide issues such as our property tax, it's going to be perceived as a referendum on Obama," he said.
Polls have given Democrats pause.
Christie, Corzine's Republican opponent is now in a statistical dead heat with the incumbent governor in the most recent polls.
In Virginia, Deeds is trailing behind his Republican opponent Bob McDonnell in the polls by an average of 9 percent, according to Real Clear Politics.
Obama won both New Jersey and Virginia comfortably in the 2008 election. His win in heavily Democratic New Jersey was expected, but the Virginia victory took analysts by surprise -- Obama was the first Democratic presidential candidate to win the state in 44 years.
Political experts believe that Obama will need Virginia again if he is to be re-elected.
"That's why you see all the Democrats coming in, is that they know there is something is at stake in the national perception of what's going on in the elections of '09," Zukin noted.
Democrats hope the president's popularity translates into voter turnout. Obama's job approval, though lower than when he entered office, hovers at just above 50 percent.
"There's always a chance that Obama could increase the energy level for Democrats generally, for those in northern Virginia - the young, the minorities throughout Virginia who tend to vote heavily democratic," Sabato explained. "These groups have simply not been engaged this year."
Zukin said those same groups will have big repercussions in New Jersey as well.
Obama "will bring some enthusiasm and really help Democrats get people to the polls and turn out," he said. "And that's especially true in our urban areas where Democrats usually win by margin of 90 to 10 percent."
Republican voters on the other hand are energized in part due to opposition on a range of the Obama administration's policies from health care reform to the handling of the economy.
Democratic wins in New Jersey and Virginia will give Obama and his party more confidence heading into the 2010 elections; losses ensure they'll have their work cut out for them.
"It's very difficult to transfer popularity to another candidate," Sabato noted. "About all you can do is increase turnout among your party activists.
"And that's where Obama could make a difference for both Corzine and Deeds," he said. "But it's not guaranteed to work in either place."