A conservative Republican who allied himself with the tea party ousted one of his own party’s top leaders in the Maryland General Assembly, even as several other veterans easily survived spirited challenges in Tuesday’s primary election.

With all precincts reporting, Del. Michael J. Hough (R-Frederick) beat Senate Minority Leader David R. Brinkley (R-Frederick) by more than 2 to 1 in one of several closely watched races featuring aggressive challenges to the old guard.

Hough had argued that Brinkley was too liberal for District 4, a Republican stronghold that includes Frederick County and a sliver of Carroll County. Hough also said Brinkley has been ineffective in opposing the expansive agenda — and tax increases — set in motion by Gov. Martin O’Malley and other Democratic leaders.

Brinkley defended taking a pragmatic approach in a state where registered Democrats outnumber Republicans by more than 2 to 1 and cast Hough as a radical whose ideology trumps common sense.

“Obviously there’s a different sentiment in the district,” Brinkley said late Tuesday after conceding. He added that low turnout contributed to his defeat in a district that turned a shade redder after redistricting in 2012. “But it’s been an honor to represent people and represent the district. It’s the people’s seat, and never really was mine in the first place.”

Hough said victory was an expression of outraged dissent over O’Malley’s record of tax hikes. “It feels great,” he said. “I just see it as a rejection of the Annapolis establishment and Martin O’Malley. People kept telling me we need change.”

More than 650 candidates filed to run for statewide offices this year, seeking positions ranging from judges to governor. The field included 425 House of Delegates candidates and 118 Senate hopefuls, said Jared DeMarinis, director of the Division of Candidacy and Campaign Finance at the Maryland State Board of Elections.

It was hard to identify an overarching theme to this year’s primary, with polls suggesting that Maryland voters were uneasy about the state’s direction — particularly its business climate and rising tax burden — but not restless enough to create the sort of upheaval that puts incumbents out on the street. Turnout was expected to be anemic: Only 47 percent of eligible voters in a recent Washington Post poll said they were paying attention to the Democratic primary for governor, the election’s marquee event.

Six races featured challenges against incumbent senators by sitting delegates in the same district, including one in which the delegate remained on the ballot despite pulling out of the race.

Among those being challenged was Sen. Ulysses Currie (D-Prince George’s), who won on Tuesday with 58.5 percent of the vote. Currie, 77, who has been in the General Assembly for nearly three decades, felt the heat during the campaign of an aggressive race run by Del. Melony G. Griffith (D-Prince George’s), having become newly vulnerable after a federal corruption trial and his subsequent rebuke by Senate colleagues.

“I don’t think he’s done a bad job. There’s just room for improvement,” said Brenda Roberts, a teacher.

Roberts, 61, said that in the past she had voted for Currie when “there really wasn’t much of an option.” This time she voted for Griffith because of her views on education and because of concerns over Currie’s ethics.

Currie was acquitted in federal court in 2011 on charges of bribery for accepting consulting fees from Shoppers Food Warehouse but was censured and stripped of his chairmanship of the Budget and Taxation Committee by the Senate.

Another Prince George’s County fixture, Del. Joseph F. Vallario Jr., won his primary and is on his way to reelection despite running in a newly redrawn two-member district after an Annapolis legislative session that included an unusual challenge to his authority.

Vallario, whose chairmanship of the House Judiciary Committee has given him substantial say over the state’s criminal laws, was forced to bend on decriminalizing marijuana after younger delegates rebelled against his opposition. Vallario was the second-highest vote-getter in the two-member district after fellow incumbent Del. Marvin Holmes, with nearly all precincts reporting.

Other noteworthy races included an unsuccessful attempt by political operative Julius Henson, who was convicted of violating state election law, to unseat Sen. Nathaniel J. McFadden (D-Baltimore), an 18-year veteran. With 100 percent of precincts reporting, McFadden held a 4-to-1 lead over Henson.

Henson ran despite a judge’s ruling that his candidacy was a violation of his probation. Prosecutors said Henson authored a robo-call intended to suppress turnout among African Americans during the 2010 governor’s race when he was handling campaign strategy for former governor Robert L. Ehrlich Jr. (R).

In Prince George’s County’s District 24, several other candidates asked voters for a second chance despite records sullied by allegations of wrongdoing.

Del. Darren M. Swain (D) fought unsuccessfully to retain the seat to which he was appointed in 2012, despite allegations by two carjacking suspects that Swain attempted to buy drugs from them and solicited one of them for sex in September. Swain — who was not charged with a crime — has denied wrongdoing.

Former delegate Tiffany T. Alston, who was removed from office after being convicted of theft, also asked voters to send her back to Annapolis. Her opponents included Gregory A. Hall, who had been nominated to replace Alston by the Prince George’s Democratic Central Committee but was rejected by O’Malley because Hall had been a drug dealer and violent criminal as a young man.

With nearly all returns in, incumbent Dels. Carolyn J.B. Howard and Michael L. Vaughn were declared winners. Erek Barron was narrowly ahead of Alston for the third nomination in the three-member district.

In Montgomery County, Sen. Richard S. Madaleno Jr. — who is one of legislature’s first openly gay members and also considered one of its most liberal — beat challenger Dana Beyer, a transgender candidate who positioned herself even further to the left.

In another closely watched Montgomery County race, former delegate Cheryl Kagan beat Del. Luiz R.S. Simmons in a fiercely fought Democratic Party primary battle for the seat being vacated by retiring Sen. Jennie M. Forehand (D).

And in Prince George’s County, the county executive’s son — Rushern Baker IV — lost his first run for public office. The younger Baker, a lecturer at the University of Maryland, came in fourth behind the three Democratic incumbents in District 22: Dels. Tawanna P. Gaines, Anne Healey and Alonzo T. Washington.

Jenna Johnson contributed to this report.