After more than 36 years representing Massachusetts in the House, Democratic Rep. Edward J. Markey will be the commonwealth’s next senator.

Backed by millions of dollars in air and ground support from national Democrats, the eighth-longest-tenured House member succeeded in holding the seat of Democrat John Kerry, who resigned to become secretary of State earlier this year.

In Tuesday’s special election, The Associated Press called the race for Markey with 82 percent of precincts reporting. At that point, Markey led Republican Gabriel Gomez, 54 percent to 45 percent.

It was Markey’s first competitive race since the 12-candidate, 1976 special-election primary that he won with 22 percent. After his April special-election primary win over Rep. Stephen F. Lynch, Democrats took no chances that the rust had worn off or that lightning wouldn’t strike twice for the GOP in the Bay State.

While most major national GOP groups sat out the spending race — likely because of doubts of its competitiveness — and few prominent Republicans joined Gomez on the trail, Democrats went all in. Markey campaigned alongside the biggest names in the party, including President Barack Obama, President Bill Clinton and Vice President Joseph R. Biden Jr.

The Democratic Senatorial Campaign Committee and Democrat-aligned Senate Majority PAC combined to spend about $2 million on TV on Markey’s behalf, mostly tying Gomez to the national GOP. Meanwhile, the Markey campaign outspent Gomez on TV, about $4.2 million to $2.3 million, and by $4 million overall.

The primary victory by Gomez, a private equity investor and former Navy SEAL, gave Republicans their best chance at repeating the success the party found in the 2010 special election for the seat of the late Edward M. Kennedy.

As a Hispanic Republican moderate on social issues, Gomez provided the GOP with the kind of candidate it needed to win in a state like Massachusetts. Still, as a first-time candidate, he lacked the political experience and personal draw that former Sen. Scott P. Brown enjoyed in 2010.

The atmospherics that allowed Brown to capitalize on those strengths were absent as well. Brown rode a wave of anti-Washington fervor and personal popularity to topple an underwhelming Democratic nominee who fumbled the seat away. But in this solidly Democratic state, Brown lost that seat by 8 points in November 2012 to now-Sen. Elizabeth Warren.

The final result of the special election came as no surprise, as Markey’s polling lead began expanding over the final weeks. He’ll be heavily favored to win the seat for a full term in November 2014. The lingering question is what’s next for Gomez.