Former state Rep. Ruben GallegoRuben GallegoWe will fight for our DREAMers Vet lawmakers urge Trump to halt heated words with North Korea Pentagon offers assessment of what conflict with NK would look like MORE defeated retiring Rep. Ed Pastor’s (D-Ariz.) choice to succeed him, former Maricopa County Supervisor Mary Rose Wilcox, in a fiery primary fight on Tuesday night.

Wilcox conceded to Gallego with a little under half the precincts reporting, though The Associated Press hadn't called the race. Gallego had 48 percent support, while Wilcox drew about 36 percent of the vote, and the other two candidates took about 15 percent combined.

Gallego was long seen as the front-runner in the contentious primary fight, despite Wilcox’s more than two decades of service in local politics in Arizona’s 7th District and Pastor’s support for her bid.

Gallego ran a youth-focused ground campaign that utilized data and technology to facilitate voter outreach in the young district, and he drew the support of a number of national progressive groups.

Wilcox, a shooting survivor, made gun violence a central focus in her attacks on Gallego, often hammering him for his B+ rating from the National Rifle Association. He accused her of voting for higher taxes while failing to pay hers on time but more often touted his own personal story, highlighting his humble beginnings and service in the Marine Corps.

Gallego is expected to easily win election in the fall to represent the deep-blue district in D.C.