Mr. Clinton's job-approval ratings remain unusually high in public polls.
They show his popularity still high but his job-approval rating falling upstate and in the suburbs.
Recent polls have shown Mr. Bush's job-approval rating to be hovering in the mid-40's or lower.
The same poll showed Mr. Lieberman's job-approval rating was 63 percent.
By the time of the 1992 election, his job-approval rating was down to 37 percent, and only 18 percent liked his handling of the economy.
Clinton's job-approval rating has held steady even as his personal favorability and trustworthiness ratings have declined.
The other changing factor is the continued drop in Mr. Bush's job-approval rating that could make him less welcome on the campaign trail.
His job-approval rating in March was 68 percent.
The poll echoed other recent surveys by indicating that the President's job-approval rating had fallen below 50 percent for the first time this year.
A poll taken November 5, 2009, showed Lincoln with a 43 percent job-approval rating, nearly 9 points down from her 2008 approval rating.