Voters in Maine are set to make significant decisions in Tuesday’s primary elections, with attention focused on a hotly contested Senate race. Republican Sen. Susan Collins is widely expected to secure her party’s nomination. On the Democratic side, progressive oyster farmer Graham Platner is in the spotlight, leading despite a campaign shadowed by controversies.

In addition, former Governor Janet Mills remains on the Democratic ballot, even though she withdrew from the Senate race in April. Several other candidates are also competing for the nomination. The polls are expected to close at 8 p.m. EDT, marking the end of a closely watched primary election day.