Updated

When Harry Truman and Lyndon Johnson accepted the reality that they could not effectively govern the nation if they sought re-election to the White House, both men took the moral high ground and decided against running for a new term as president. President Obama is facing a similar reality—and he must reach the same conclusion.

He should abandon his candidacy for re-election in favor of a clear alternative, one capable not only of saving the Democratic Party, but more important, of governing effectively and in a way that preserves the most important of the president's accomplishments. He should step aside for the one candidate who would become, by acclamation, the nominee of the Democratic Party: Secretary of State Hillary Clinton.

Never before has there been such an obvious potential successor—one who has been a loyal and effective member of the president's administration, who has the stature to take on the office, and who is the only leader capable of uniting the country around a bipartisan economic and foreign policy.

Never before has there been such an obvious potential successor—one who has been a loyal and effective member of the president's administration, who has the stature to take on the office, and who is the only leader capable of uniting the country around a bipartisan economic and foreign policy.

Certainly, Mr. Obama could still win re-election in 2012. Even with his all-time low job approval ratings (and even worse ratings on handling the economy) the president could eke out a victory in November. But the kind of campaign required for the president's political survival would make it almost impossible for him to govern—not only during the campaign, but throughout a second term.

Patrick Caddell served as a pollster for President Jimmy Carter. Doug Schoen, who served as a pollster for President Bill Clinton, is author of several books including the forthcoming "Hopelessly Divided: The New Crisis in American Politics and What It Means for 2012 and Beyond" (Rowman and Littlefield). Both are Fox News contributors. Together with former New York Republican Rep. John LeBoutillier, they co-host "Campaign Confidential" on FoxNews.com Mondays at 2 p.m. ET. To continue reading their column on Hillary Clinton and Barack Obama in The Wall Street Journal, click here.