BOSTON - Massachusetts may account for about 2 percent of the nation's population, but when it comes to nurturing White House dreams, the Bay State is a political boomtown.

Since 1960, at least half a dozen Massachusetts politicians have launched serious campaigns for president, while a handful of others have toyed with the idea.

Three captured their political party's nomination and one, John F. Kennedy, went on to occupy the office.

The difference this election cycle is that the politician aiming to be the fourth major-party nominee from Massachusetts in the last five decades is a Republican, Mitt Romney.

"You can say that all governors and senators see themselves as potential presidential contenders," said Boston College political science professor Marc Landy. "What's perhaps more surprising is how successful Massachusetts politicians have been in making themselves very serious contenders."

What makes the streak even more unusual is Massachusetts' reputation as one of the nation's most liberal states.

Timothy Vercellotti, associate professor of political science and polling director at Western New England College, chalks up the string of would-be Massachusetts presidential hopefuls to a number of factors - from the state's obsession with politics, to the potential brain power supplied by local institutions like Harvard University and MIT, to its location on the Northeast corridor linking Washington, New York, and Boston.

The state's recent run of presidential contenders began in 1960 when then-Sen. John F. Kennedy secured the Democratic nomination on a first ballot and went on to narrowly defeat Republican Richard Nixon.

Kennedy was the first president to hail from the state since former Republican Gov. Calvin Coolidge, then vice president, took the oath of office in 1923 after the death of President Warren Harding.

Prior to Coolidge, the state could claim two other chief executives - John Adams, the nation's second president, and his son John Quincy Adams, the sixth president.

After Kennedy's assassination in 1963, his brother, Sen. Robert F. Kennedy (D., N.Y.), was assassinated in 1968 during his campaign for the White House. And their younger brother, U.S. Sen. Edward M. Kennedy, unsuccessfully challenged President Jimmy Carter for the Democratic nomination in 1980.

The loss marked the end of the Kennedy family's efforts to retake the presidency and paved the way for other Massachusetts candidates who lacked some of the aura and political baggage of the Kennedy clan.

First was former Gov. Michael Dukakis, who tried to ride crest of the state's economic boom of the 1980s, dubbed the "Massachusetts Miracle." Dukakis secured the Democratic Party's nomination in the 1988 contest, but lost to the GOP nominee, then-Vice President George H.W. Bush.

Bush also had ties to Massachusetts. He was born in the state, and although his family quickly moved to Connecticut, he later became a student leader at Phillips Academy in Andover, Mass.

Just four years later, another politician of modest means got into the race: Democrat Paul Tsongas, who had left the Senate in 1984 after being diagnosed with the cancer. He looked to jumpstart his candidacy with his fiscal conservatism and the proximity of his hometown of Lowell, Mass., to New Hampshire and its first-in-the-nation primary.

Tsongas failed to secure the 1992 nomination, but Massachusetts wouldn't have to wait long before another favorite son would thrust himself into a presidential campaign.

In 2003, Democrat John Kerry, a Vietnam veteran who first won election to the Senate in 1984, announced his candidacy. His foes tried to cast him as a Massachusetts liberal, pointing to his decision to oppose the Vietnam War after being awarded three Purple Hearts. He lost the 2004 election to President George W. Bush.

By then, Romney was already laying the foundation for his pursuit of the GOP nomination for the presidency. Despite a hard-fought campaign in 2008, he lost the party nod to Sen. John McCain of Arizona.

But Romney never really stopped running for president. After the election of Barack Obama, he set about trying to position himself as the 2012 GOP nominee - a mission he has all but accomplished.

Even though he's a Republican, Romney has also been dogged by the "Massachusetts liberal" label, mostly for signing the state's landmark 2006 health-care law, which became the model for Obama's 2010 health-care overhaul. But Romney has vowed to repeal the federal law if elected.

Since 1960, a number of Massachusetts politicians have also toyed with the idea of running for president, including Republican Gov. William Weld, Democratic Boston Mayor Kevin White, and Sen. Henry Cabot Lodge Jr.

Vercellotti said it's hard not to anticipate the trend continuing, pointing to a handful of current state political figures with potential national traction, including Gov. Deval Patrick and Democratic Senate candidate Elizabeth Warren.