President Obama’s support is eroding among elements of his base, and a yearlong effort to recapture the political center has failed to attract independent voters, according to the latest New York Times/CBS News poll, leaving him vulnerable at a moment when pessimism over the country’s direction is greater than at any other time since he took office.

The president’s effort to seize the initiative on the economy was well received by the public, and clear majorities support crucial pieces of his new job-creation program. But despite Mr. Obama’s campaign to sell the plan to Congress and voters, more than half of those questioned said they feared the economy was already in or was headed for a double-dip recession, and nearly three-quarters of Americans think the country is on the wrong track.

Republicans appear more energized than Democrats at the outset of the 2012 presidential campaign, but have not coalesced around a candidate. Even as the party’s nominating contest seems to be narrowing to a two-man race between Mitt Romney and Gov. Rick Perry of Texas, a majority of their respective supporters say they have reservations about their candidate. Half of Republicans who plan to vote in a primary say they would like more choices.

A snapshot of the Republican Party, four months before the first primary ballots are cast, shows that voters are evenly divided between preferring a presidential nominee who can defeat Mr. Obama or one who aligns with them on most issues. A majority of voters who support the Tea Party movement place a higher priority on winning back the White House.