WASHINGTON (CNN) -- Touting his ability to transcend Washington's "petty politics," former Massachusetts Gov. Mitt Romney formally declared his candidacy for the Republican presidential nomination Tuesday in Michigan where his father once served as governor.

"We are weary of the bickering and bombast, fatigued by the posturing and self-promotion," Romney told supporters at the Henry Ford Museum in Dearborn. "For even as America faces a new generation of challenges, the halls of government are clogged with petty politics and stuffed with peddlers of influence."

"It is time for innovation and transformation in Washington," the Massachusetts Republican added. "It is what our country needs. It is what our people deserve."

The speech largely stressed conservative themes including the need for less taxes and government, increased border security, and the strengthening of the American family.

On Iraq, Romney said an early withdrawal would be "devastating," and argued that U.S. forces must stay involved in the region if there is a "reasonable prospect of success."

"Our wisest course is to seek stability in Iraq, with additional troops endeavoring to secure the civilian population."

Romney also emphasized the need for a mother and a father "in the life of every child," and the need for "leaders who strive to demonstrate enduring values and morality."

Romney follows his announcement with a four-day six-state tour, hitting several crucial caucus and primary states including Iowa, New Hampshire, and South Carolina.