Last year, it seemed like Stephen F. Lynch might have to worry.

The South Boston Democrat has served in Congress since 2001, representing parts of the city and the South Shore. He has shown an independent streak, most infamously when he voted against Obamacare in 2010.

Lynch drew two opponents: Christopher L. Voehl of Milton and Brianna Wu of Dedham, known for her role in the so-called Gamergate controversy, which drew attention to online misogyny.

But neither has gained much traction.

Some Democrats may never forgive Lynch’s Obamacare vote, but he’s helped protect the law in the years since. The Globe endorses him for the Democratic nomination on Sept. 4.