National Republicans cheered former Navy SEAL Gabriel Gomez’s Massachusetts primary victory, but Democratic Congressman Ed Markey enjoys tremendous advantages in the special election to replace former U.S. Sen. John Kerry.

Tuesday’s primary elections set up an eight-week sprint to the June 25 election.

In Markey, the race pits a longtime liberal politician known for environmental advocacy against Gomez, a fresh-faced social moderate with a distinguished biography and untested political skills. On paper, it looks like a competitive contest, but Republicans quietly concede that Markey is the strong favorite in a state where only about 11 percent of voters are registered Republicans.

“As we’ve shown before in the state, anything can happen in a special election,” said Republican strategist Ron Kaufman, Massachusetts’ national committeeman.

Indeed, little-known Republican state Sen. Scott Brown stunned Democrats in his 2010 special election U.S. Senate victory in a contest that became a referendum on Obama’s health care overhaul. So far, at least, this race has drawn little national interest, even before being overshadowed by the Boston Marathon bombings.

And unlike the last special election, this one will have little bearing on the immediate balance of power in the U.S. Senate, where Democrats have an effective 55-45 majority.

But Massachusetts Democratic party leaders promised they would not repeat the mistakes of the last special contest, when they largely took success for granted.

“We have absolutely learned a lesson. As long as I’m around, we will never leave primary day thinking we’re all set,” Massachusetts Democratic Party chairman John Walsh said Tuesday, vowing an aggressive grassroots strategy to rally Democrats across the state behind Markey.

Gomez, 47, won a three-way primary against former U.S. Attorney Michael Sullivan and state Rep. Daniel Winslow. Markey, 66, a member of Congress for the past 36 years, defeated fellow U.S. Rep. Stephen Lynch on the Democratic side.

“This election, ladies and gentleman, will not be easy,” Markey said in his primary victory speech, suggesting that national Republicans were prepared to “move mountains of money to buy this election.”

Gomez, meanwhile, painted Markey as a longtime Washington insider in a speech that included moments of Spanish. He said he was playing Little League baseball when Markey was first elected to Congress.

In many ways, Gomez fits the profile of a new brand of politician that Republican leaders are looking for. The Republican National Committee released a report in March calling for better minority outreach and more inclusive tones on immigration and social issues.

Gomez is the son of Colombian immigrants and speaks fluent Spanish. He supports gay marriage but says it should be decided state by state. He personally opposes abortion, citing his Catholic faith, but hasn’t advocated overturning Roe v. Wade.

Over more than three decades in Congress, Markey quietly built a legislative portfolio that included work on energy, telecommunication, national security and the environment. When oil began spilling into the Gulf of Mexico after an offshore explosion, Markey pushed to make live video footage of the spill available.

The Democrat begins the race with a significant financial advantage. He led all other candidates in fundraising and had won the backing early on of Kerry and a large segment of the Democratic establishment.

Gomez, who launched a career in private equity after leaving the military, has already loaned his campaign at least $600,000.