MARYLAND HEIGHTS, Mo. — Former Navy SEAL Eric Greitens, a political newcomer who was once courted to run for Congress as a Democrat, on Saturday launched a Republican campaign for Missouri governor in 2016.

Greitens, 41, is already the top fundraiser in a crowded GOP field thanks to an exploratory campaign committee that's raised more than $1 million in recent months, boosting his total haul to more than $2 million.

He touted both his military background and lack of political pedigree before a crowd of several hundred supporters at an announcement in suburban St. Louis near his childhood home.

"I'm running for governor because we need a political outsider to move Missouri forward," Greitens said. "We have a political class of corrupt consultants, well-paid lobbyists, and career politicians who have been in Jefferson City for decades. They have produced nothing for us but embarrassment and failure."

Greitens grew up in St. Louis County, was a Rhodes Scholar after graduation from Duke University, served in the Afghanistan and Iraq wars and as White House fellow. He's written three books that combine stories of his military service and humanitarian work with lessons on leadership. He founded the nonprofit group The Mission Continues, which connects veterans with volunteer work to ease the post-military transition.

He drew the loudest cheers with a call to extend term limits to all statewide offices and ban lobbyist gifts to state lawmakers.

"I will defeat you, I will expose your lies, I will root out your corruption, and I will see you out of the people's Capitol," said Greitens, adding his own lifetime pledge to never lobby government.

Those words resonated with Tom Long, a St. Louis police officer, who brought his 4-year-old daughter and 1-year-old son. The candidate's stump speech included the observation that "the lives of our cops matter" — an indirect reference to the "Black Lives Matter" movement that emerged after recent fatal police shootings, including the August 2014 death of Michael Brown Jr. in nearby Ferguson.

"He's a proven leader," Long said. "He leads by example."

Greitens' entrance into the race makes him at least the fourth declared Republican contender to succeed Democratic Gov. Jay Nixon, who after seven years in office is barred by term limits from seeking re-election.

Former U.S. Attorney and onetime Missouri House Speaker Catherine Hanaway, Lt. Gov. Peter Kinder and Springfield state Sen. Bob Dixon have officially entered the race. Suburban St. Louis businessman John Brunner is expected to join as well, with an early October announcement scheduled.

State auditor Tom Schweich was an early challenger to Hanaway, announcing his candidacy in January before committing suicide weeks later.

Attorney General Chris Koster — a former Republican who switched parties as a state senator in 2007 — is the only Democrat who has said he intends to seek the state's top executive office.

The campaign committee formed in February allowed Greitens to collect money before publicly declaring his intent. He's already well ahead of Hanaway, who has been running for governor for more than a year.

Ballentine reported from Jefferson City, Missouri.