Dan Helmer (Jahi Chikwendiu/The Washington Post)

Democrats are already gunning for the last Republican-held House of Delegates seat in Northern Virginia after the 2017 blue wave nearly erased the GOP’s majority in the General Assembly.

Army veteran Dan Helmer announced Thursday that he will challenge Del. Tim Hugo (R-Fairfax) next year.

The move comes two months after Helmer lost the Democratic primary to run against Rep. Barbara Comstock.

Helmer made national headlines for provocative campaign ads, including one that compared President Trump to Osama bin Laden, but he still came in fourth place.

“Whatever the level, this has always been about a continuation of the service that inspired me to join the military,” he said.

The early announcement shows Democrats are serious about trying to win control of the House of Delegates that Republicans hold by the narrowest possible majority.

Republicans have already labeled freshman Democrats the “Extreme 15” in an effort to paint them as too liberal for Old Dominion.

Hugo, who has represented the district for 15 years, said he’ll continue to work to combat human trafficking, reduce tolls, bury power lines in Haymarket and fill potholes.

“My constituents want a dedicated public servant focused on local issues and constituent service, not someone shopping for a political future,” he said in a statement, referring to Helmer.

The district includes parts of Fairfax County, where Helmer lives, and northern Prince William County.

Gov. Ralph Northam (D) won the once reliably red district by 11 percentage points, and Hillary Clinton won it by 8 points.

Democrat Donte Tanner came within about 100 votes of unseating Hugo last year and had publicly announced his plans to run again in 2019.

But Tanner bowed out, citing family considerations, and endorsed Helmer in a video that emphasized their shared military roots — Tanner is an Air Force veteran — and young children.

Fourteen state lawmakers and Sharon Bulova, chairman of the Fairfax County Board of Supervisors, joined Tanner in endorsing Helmer.

A combat veteran and Rhodes Scholar, Helmer ran for Congress on the strength of his personal story and the credibility he said it gave him on gun control and education.

During the congressional primary, Helmer also produced an undercover video in which he legally purchased a semiautomatic assault rifle at a gun show in minutes without a background check, and an ad in which he sang “You’ve Lost the Centrist Feeling,” to a Comstock look-alike.