Former US President Barack Obama headlined a fundraiser for Senate Democrats in the Washington, DC area on October 7, his first appearance at a Democratic Senatorial Campaign Committee event this midterm cycle.

The event included a conversation with Delaware Senator Lisa Blunt Rochester, a DSCC vice chair, on the importance of flipping the Senate and the stakes of the November 3 election.

Republicans hold a 53 to 47 Senate advantage. Democrats need a net gain of four seats to take control, with 35 seats on the ballot.

The Cook Political Report rates seven races as tossups: Alaska, Iowa, Maine, Michigan, New Hampshire, Ohio and Texas. North Carolina leans Democratic and Kansas leans Republican.

Obama has been selective this cycle but has campaigned in Texas and Iowa. He will headline a Detroit rally on October 24 alongside Michigan Senate nominee Abdul El-Sayed.

The fundraiser took place at the Great Falls, Virginia home of Warren Thompson. It was Obama’s first appearance at a DSCC event this midterm cycle, with the November 3 election less than a month away.