When Maryland approved its new congressional map in October, two things appeared clear: The district long held by Republican Rep. Roscoe G. Bartlett would be up for grabs, and the seat’s new lines were drawn to give a boost to one particular Democrat — state Senate Majority Leader Robert J. Garagiola.

Yet with less than three weeks left before Maryland’s April 3 primary, what could have been a coronation has turned into a street fight, as Garagiola is locked in a heated contest with financier John Delaney for the Democratic nomination.

“I think it’s fair to say Garagiola started with an advantage in this race, but the question is whether Delaney’s spending can close the gap,” said David Wasserman, House editor for the nonpartisan Cook Political Report.

With Senate President Thomas V. Mike Miller Jr. (D-Calvert) playing a key role in its drafting, the reshaped district just so happens to include Garagiola’s Germantown home while excluding those of some other prominent Montgomery County Democrats who might have wanted to run.

That includes Delaney, whose Potomac home sits just outside of the new 6th District, which includes Western Montgomery and the more rural Maryland panhandle. Delaney, the founder of the Chevy Chase commercial bank CapitalSource, decided to run anyway — candidates are not required by law to reside in the district — and has brought his considerable wealth and Democratic connections to bear on the race.

Rob Garagiola talks with supporters as he kicks off his congressional campaign in Maryland's 6th District on Nov. 1. (Katherine Frey/THE WASHINGTON POST)

Three other Democrats are running, including Air Force physician Milad Pooran, but Garagiola and Delaney are widely considered the front-runners.

Delaney’s campaign has been touting recent endorsements, including from former president Bill Clinton and state Comptroller Peter Franchot. Delaney is on the air with television and radio ads emphasizing the Clinton nod, with more to come in the closing days of the race.

“This race is neck and neck, and we’ve seen the momentum shift in the last 10 days to John Delaney,” said Justin Schall, Delaney’s campaign manager. “We are going to continue to build on that momentum every day between now and Election Day.”

Delaney’s campaign will report soon to the Federal Election Commission that it has raised more than $700,000 since the beginning of January, and that does not include what Delaney — who is worth upward of $50 million — has put into the race. He has said he is willing to spend more than $1 million of his own money to win the primary.

Garagiola, whose campaign would not provide its latest fundraising totals, has not run any ads in the race, focusing on direct mail and grass-roots support instead.

“The Garagiola campaign has been implementing its strategic plan for months, building the support of member-driven Democratic and progressive groups that are absolutely critical to win a Democratic primary,” said Garagiola campaign manager Sean Rankin, adding: “So let Delaney buy his TV ads and waste his money. Even my little boys, 6 and 8, know you can’t buy real friends; you have to earn them.”

Garagiola has a clear advantage in winning support from elected officials in Maryland, boasting the endorsements of more than two dozen members of the General Assembly, Lt. Gov. Anthony G. Brown and Rep. Steny H. Hoyer. (Democratic insiders said Garagiola’s allies have urged Reps. Chris Van Hollen and John P. Sarbanes to join Hoyer in endorsing Garagiola, but they chose to stay neutral.)

Organized labor remains an influential force in Democratic primaries, and Garagiola has gobbled up the endorsements of nearly every major union, including the AFL-CIO, Service Employees International Union, American Federation of State County and Municipal Employees and the National Education Association.

Those unions can mobilize thousands of members to help knock on doors and get voters to the polls April 3. Garagiola also recently picked up the backing of the liberal grass-roots group MoveOn.org.

“Garagiola probably has a slight lead because of infrastructure, but at least the Montgomery County portion [of the district] has been known to buck the conventional wisdom,” said a Maryland Democratic strategist unaffiliated with either campaign.

Each man has sought to project a positive agenda. Garagiola has emphasized his experience on health-care issues and work for middle-class families, while Delaney is in the midst of releasing one detailed policy paper a day for five days.

But the tone of the race has often been negative. Garagiola has criticized Delaney for, among other things, refusing to release his tax returns, for contributing money to Republican Rep. Andy Harris’s 2010 congressional campaign and for his company’s alleged efforts to cut its tax bill.

Delaney, in turn, has accused Garagiola of trying to hide his past career as a federal lobbyist and of lobbying for a notorious-in-Democratic-circles Republican firm, Berman & Co. And Delaney’s campaign has needled Garagiola for supposedly having a gerrymandered seat handed to him by allies in the General Assembly.

“This race conforms to what we’re seeing in other Democratic primaries, with one candidate calling the other an ‘insert-state-capitol-here insider,’ and the other calling his opponent a closet Republican,” Wasserman said.

Neither campaign has released any recent polling. A survey conducted for Delaney in early February by Garin-Hart-Yang Research Group showed a wide-open race, with each man getting 20 percent in a head-to-head race and nearly 60 percent of likely primary voters undecided.