In running for re-election, Barack Obama commands the most powerful democratic platform in world history and the greatest backdrop, the White House. A seemingly casual announcement in a TV interview can trigger a political earthquake, as Obama did when he endorsed gay marriage. But the president’s magnificent residence can also be what Harry Truman called the Great White Jail.

Presidents are handcuffed by their power. Presidential statements can crash financial markets or start wars. The dignity of the presidency also inhibits, even in today’s brutal political environment. Obama’s campaign ad attacking Mitt Romney’s record at Bain Capital made some Democrats squirm as Republicans labeled the president “another gut-punching politician from Washington.”

The ambivalence about presidents politicking goes back to the nation’s founding. George Washington liked “going on tour,” getting “huzzahed” north and south – but, reflecting his contemporaries’ distaste for democracy, he avoided explicit political talk. When the less popular President Martin Van Buren toured before his 1840 re-election campaign, his fellow Democrats feted him. Nevertheless, the new partisanship polarizing American politics had Whig Party critics denouncing Van Buren’s activities as “undignified” and “insulting,” while mocking “His Majesty, King Martin the First.”

A cartoon depicted the obstacles facing President Martin Van Buren's reelection effort in 1840. Weighed down by a bundle labeled "Sub Treasury," Van Buren followed the lead of Andrew Jackson toward the White House.

In 1864, Abraham Lincoln said he was too busy to campaign for reelection — a common presidential posture. Still, “Honest Abe” was a crafty pol, who was “too busy looking after the election to think of anything else,” according to his treasury secretary, William Pitt Fessenden.

This posture of presidential passivity persisted, even after William Jennings Bryan’s 18,000 mile 1896 stumping tour ended the charade for challengers, who now campaigned openly and vigorously. The hyperkinetic President Theodore Roosevelt chafed under the restrictions in 1904, comparing it to “lying still under shell fire” when he was a Rough Rider. Still, T.R. understood that no matter what he did his election would be a “referendum on Roosevelt,” as one aide said.

The impression of energetic politicking Theodore Roosevelt conveyed — even while he felt constrained — propelled presidents more explicitly into politics. In the 1930s and 1940s, Franklin D. Roosevelt perfected the presidential techniques of campaigning by governing and scoring political points by pretending to be nonpolitical. Roosevelt showered voters with governmental goodies while parrying reporters’ political questions by saying “I don’t know nothin’ about politics.” Critics wondered how to criticize him as he saved starving children. Opponents “could only talk,” the Times columnist Arthur Krock marveled, as Roosevelt announced new initiatives in his campaign addresses. “The president acted.”

Unfortunately, F.D.R.’s act reinforced the traditional impression that politicking besmirched the president. Even while presiding over his party as adeptly as he presided over the nation, even while understanding how to sell policies not just develop them, Roosevelt disrespected the democratic dialogue. He treated the sacred act of soliciting voters’ support as a profane act of crass self-promotion.

In 1964, Lyndon Johnson, despite being a Roosevelt protégé, could not keep up the charade of acting presidential for long. “Get in your cars and come to the speakin’,” he yelled as he motorcaded – and showered farm aid, disaster relief, food stamps and pay raises on the communities he visited.

Eight years later, Richard Nixon took Roosevelt’s public prudishness and private ruthlessness to such extremes that he ruined his presidency. In 1972, President Nixon said that he would win re-election simply by “doing my job.” White House staffers froze out reporters who dared treat Nixon as a candidate, even as he privately called the campaign “a fight to the death.”

The Watergate revelations made all politicians look crooked. Nixon’s defense that every president acted ruthlessly resonated with the post-1960’s adversary culture epitomized by the hypercritical news media. Conflict-oriented stories emphasized politicians’ moral failings and the brutality of American politics.

The Watergate debacle prompted a new presidential primness. Gerald Ford and Jimmy Carter each followed a “Rose Garden strategy” while running for re-election, obscuring their political calculations in moralistic claims that the nation needed them working in the White House. This return to a nineteenth-century delicacy culminated in Michael Dukakis’s 1988 campaign. Dismissed by one reporter as “just a brain in the jar,” the bloodless Massachusetts technocrat who was not even yet president was so busy declaiming what was and wasn’t “worthy of a presidential campaign,” he blew a 20-point summertime lead.

As both candidate and president, Bill Clinton combated the growing perception that the Democrats had become the party of high-minded, long-winded, weak-chinned wimps who could not take a political punch. Clinton combined a Rooseveltian charm and duplicity with a shameless Nixonian ruthlessness that reassured Democrats after so many Reagan-era losses. “I find it appalling that a lot of well-established people don’t understand how important political skills are to governing,” James Carville, Clinton’s chief strategist, complained. If you don’t win, “you are never going to get anything done.”

Even before he became President, Barack Obama struggled with these mixed messages. In 2008, some aides welcomed stories that this high-minded philosopher-politician could be the tough Chicago pol when necessary. Now, Obama’s supporters are using the recent backlash against his Bain ads to emphasize that Obama “didn’t survive and triumph in battles with Chicago politicians, some of whom resembled dockside thugs, because he’s made of cotton candy,” as the Democratic consultant Donna Brazile wrote recently.

Obama’s image is a hologram, sometimes hovering above the fray, sometimes plunging into the political muck. With his Dream Act-like executive order halting the deportation of illegal immigrants who came to the United States as children, Obama is campaigning by governing as F.D.R. did, approaching the shamelessness of L.B.J. and the desperation of Clinton, banking on Americans’ appetite for presidential remorselessness. No president can govern effectively without being a consummate politician, which includes knowing how to sell yourself, push your agenda, trim, spin, compromise, build coalitions, punish enemies and trash opposing ideas.

While presidents also need to act proportionately and be statesmen-like, the presidential primness that began with George Washington was antidemocratic, reflecting the founders’ fears of mob rule. In our more democratic era, we still should fear demagogues while cherishing popular politics. The challenge is particularly difficult these days when politics seems so poisonous and presidents shrewdly seek insulation from the toxicity.

Treating politics as disreputable demeans democracy. The expanded involvement of voters in politics and the increased pressure on presidents to communicate with voters are among America’s greatest democratic achievements of the last two centuries. Political skills in the White House are like guns in Dodge City. You want your guys to have them but worry when the bad guys wield them. Perhaps it’s time to resurrect the 1964 complaint of the historian James MacGregor Burns, as the White House yet again becomes a “round-the-clock, round-the-year campaign headquarters.”