BOSTON — Republican Gov. Mitt Romney said Wednesday that he will not run for a second term next year, fueling speculation he will seek the 2008 Republican presidential nomination.

"My decision comes down to this: In this four-year term, we can accomplish what I set out to do. In fact, we've already accomplished a great deal," he said.

Reporters questioned him afterward about whether he would run for president, but Romney said that decision is "a lifetime away."

"(Sen.) John McCain said he thinks about being president every day in the shower," he said. "I guess I will turn to the words of 'Star Wars': It's in a galaxy far, far away."

Should he run for president, Romney will need to break through a pack of more prominent Republicans. Potential rivals include McCain of Arizona and former New York Mayor Rudolph Giuliani.

There has also been an undercurrent of concern among Christian conservatives, particularly in the vital South, prompted by his membership in The Church of Jesus Christ of Latter-day Saints.

"His religion is a significant problem because many evangelical Christians do not believe that Mormons are Christians," said Stuart Rothenberg, an independent political analyst in Washington. "To the extent that we have controversial religions in this country, LDS is one of them."

Romney's 2002 election in Massachusetts followed a long business career and came close on the heels of his success as president of the Salt Lake Olympic Organizing Committee from 1999-2002.

Romney, son of former Michigan Gov. George Romney, has spent less than three years in elective office, but in that time the state has closed a $3 billion budget deficit without raising taxes, schools have scored first in national math and science tests and Romney held out until the Legislature gave him a tough new drunken-driving law.

Romney's decision was not a complete surprise. He declared earlier this year that he was "testing the waters" for a White House run.

Serving just one term allows Romney, 58, to leave with his record intact and focus on the presidential race, analyst Rothenberg said.

"He doesn't want to run for re-election because he could possibly get beat," he said. "And he doesn't want to run for re-election because he could possibly win, and then have to turn around and start running for president immediately."

Romney said he sat down with his wife, Ann, to make a list of the things he still wanted to do as governor. "Frankly there was very little to do for a second term that I could realistically accomplish," he said.