The decision by Sen. Barbara A. Mikulski to retire in 2016 has created an unexpected contest not only for her coveted seat, but it could put several House districts in play for the first time in more than a decade.
Seven of Maryland's eight members of the House of Representatives — six Democrats and one Republican — say they might run for the open seat, a rare opportunity in a state where congressional turnover is far slower than the national average.
Because lawmakers cannot run for two seats at once, aiming for the Senate means abandoning a job in the House.
Former Gov. Martin O'Malley — a formidable fundraiser with statewide recognition whose entry might have cleared the field of potential challengers — said Tuesday that he would not run for the seat. The Democrat is considering a White House bid.
On the Republican side, the decision by retired Johns Hopkins neurosurgeon Ben Carson to form an exploratory committee for a presidential run quelled hopeful talk among some conservatives that the Florida resident might return to Maryland to run for the seat.
Rep. Chris Van Hollen appeared to be the member of the state's congressional delegation moving most rapidly toward a possible candidacy. In a brief interview Tuesday on Capitol Hill, the Montgomery County lawmaker said he is calling other Democrats in the state in an effort to lock down support.
"I'm taking a very serious look at it," said Van Hollen, the top Democrat on the House Budget Committee and a former chairman of the House Democrats' campaign operation. "It's a question of talking it over with the family, first and foremost, and secondly making sure I have something I can contribute to the debate."
If he decides to run, Van Hollen could face several other candidates in the April 5 primary — and a political landscape that will shift depending on who else enters. Aides to Democratic Reps. Donna F. Edwards of Prince George's County and John Sarbanes of Baltimore County confirmed Tuesday that their bosses are looking at possible campaigns.
Democratic Reps. C.A. Dutch Ruppersberger of Baltimore County, John Delaney of Montgomery County and Elijah E. Cummings of Baltimore had previously indicated interest, along with Baltimore Mayor Stephanie Rawlings-Blake.
"I've got a lot of good friends who all want to run," said Ruppersberger, who said he has been in touch with his pollster to gauge support in Maryland. "You want to look at all opportunities."
Rep. Andy Harris, a Baltimore County Republican, is thinking about a run.
If even half of the potential candidates were to launch a Senate campaign, it would open up the possibility of a turnover of House seats the likes of which Maryland has not seen in years. Several state lawmakers — who would be able to run in 2016 without risking their seats in Annapolis — are closely eyeing the jockeying for Mikulski's job.
For example, if Harris ran, Kathy Szeliga, the minority whip in the House of Delegates and a longtime Harris ally, said, "I would have to take a look at it, yes."
Similarly, a Rawlings-Blake candidacy would open up a high-profile contest for City Hall. An aide to the mayor said she will decide in the coming weeks.
Racial and geographic politics will also come into play as would-be candidates circle, observers said. Black candidates could split the African-American vote in Baltimore and Prince George's County, just as multiple white candidates from Montgomery County could help a black candidate.
The average tenure of House members nationwide is 8.8 years, according to the nonpartisan Congressional Research Service. In Maryland, the average is 12.5 years. Delaney, first elected in 2012, is the newest member of the delegation. Harris, elected in 2010, is the second-most recent arrival.
Maryland has been home to some compelling congressional contests in recent years. In the 6th District, redrawn after the 2010 Census, Delaney challenged an establishment pick in the 2012 Democratic primary and went on to beat incumbent Republican Rep. Roscoe G. Bartlett in the general election. Four years earlier, Harris beat longtime Rep. Wayne T. Gilchrest in a Republican primary.
But competitive races generally have been the exception — and that has built a pent-up demand for rising political stars.
John T. Willis, a political scientist at the University of Baltimore, suggested that Maryland's proximity to Washington helps explain the longevity of its congressional delegation. Being able to return home every night makes it easier to juggle family demands and stay in touch with constituents.
"It makes it easier for one's career," Willis said. "Getting home is easier than for members from the Plains states."
Republicans say they see opportunity in the potential infighting.
"I hope all of them run," quipped Joe Cluster, the state GOP's executive director.
"It's going to be very tough for us to win a statewide race in a presidential election year," he said. "But on the congressional side, there's some real opportunities in a couple of seats."