Obama and Pelosi will attend a fundraiser at green activist Tom Steyer's home.
Kathleen Matthews is running for the Maryland seat left open by Rep. Chris Van Hollen.
The election was to replace former Rep. Alan Nunnelee, who died of brain cancer.
Mario Trujillo 05/30/15 11:39 AM EDT
Turnout could be higher in the Ro Khanna-Rep. Mike Honda rematch in California.
Scott Wong 05/28/15 12:22 PM EDT
Scott Wong 05/27/15 04:24 PM EDT
The poll of GOP primary voters in the district shows Paul Babeu with the early edge.
Rep. Frank Guinta allegedly took more than $350,000 in illegal campaign donations.
Rep. Frank Guinta (R-N.H.) is in hot water over campaign finance violations.
House Democratic leaders had urged members to oppose the spending bill.
Dems hope they can take the Staten Island seat back in 2016.