Democrat Tom Nelson dropped out of the Wisconsin Senate primary on Monday and threw his weight behind Lt. Gov. Mandela Barnes, a move that aims to consolidate progressive Democratic support in one of the party’s tightest primary battles.

Nelson, who served as the Outagamie County executive since 2011, delivered the announcement on Twitter and said “We ran out of money. So I am suspending our campaign and endorsing the one candidate not trying to buy this election: #TeamMandela.”