What to watch: Democratic primary voters in Massachusetts will choose between experience and change on Tuesday as progressive insurgents challenge long-serving members of Congress in one of the most liberal states in the country. Read more

Ayanna Pressley, the first black woman to serve on the Boston City Council, is challenging the 10-term incumbent, Representative Michael Capuano, in the Seventh Congressional District.

Tahirah Amatul-Wadud, a black civil rights lawyer, is taking on Representative Richard Neal, first elected in 1989, in the First Congressional District. She is among candidates in other states who would break a barrier in Congress, which has no Muslim women.

Brianna Wu, a video game developer, is facing Representative Stephen Lynch, first elected 17 years ago, in the Eighth Congressional District. Christopher Voehl, a pilot, is also running.

Republicans will also pick their nominee to run against Senator Elizabeth Warren in November, a race that could be the opening salvo to weaken her ahead of the 2020 presidential race.

There are three candidates vying to challenge Ms. Warren, a Democrat who faces no primary opponents. They are Geoff Diehl, a state representative; John Kingston, a business executive; and Beth Lindstrom, who was a cabinet official under Gov. Mitt Romney.

Two Democrats — Jay M. Gonzalez, a cabinet member under Gov. Deval Patrick, and Bob Massie, an environmental activist — are running for their party’s nomination for governor.

The incumbent, Charlie Baker, a Republican, is expected to survive a primary challenge from a far-right minister, Scott D. Lively. Polls say Mr. Baker is the most well-liked governor in United States.

— LIAM STACK