Election live updates: Ed Markey and Seth Moulton chase Senate Democratic primary win in Massachusetts

What to know today MASSACHUSETTS PRIMARIES: Today’s primaries in Massachusetts have turned into the test battlefield in the Democratic Party’s generational divide, with several longtime legislators facing off against younger challengers. WHAT TO WATCH: Massachusetts Sen. Ed Markey, 80, is facing a primary challenge from 47-year-old Rep. Seth Moulton amid deep frustration among Democratic voters with the party’s aging leadership. Read what Steve Kornacki is watching in his new subscriber-exclusive newsletter, The Data Dive. MAIL-IN VOTING WHISTLEBLOWER: An anonymous federal official warned in a whistleblower complaint this week that the technical system the U.S. Postal Service built to involve itself in mail voting is flawed, untested and likely to cause major disruptions in this fall’s midterm elections if it is implemented. VENEZUELAN OIL: The White House released more details last night on what President Donald Trump has touted as the biggest oil deal in history as he pushes to tap into Venezuela's oil.

Live updates and the latest news as Ed Markey and Seth Moulton chase the Democratic nomination for Senate in Massachusetts