Two Democratic vice presidents are teaming up to head off a possible Republican victory in Massachusetts' special Senate election.

The White House says Vice President Joe Biden and former Vice President Al Gore will attend a fundraiser in Washington on Tuesday for Representative Ed Markey. He's running against Republican Gabriel Gomez to replace former Senator John Kerry, who stepped down to become secretary of state.

Markey won't be at the fundraiser.

Democrats have been sending in their biggest players ahead of the June 25 election. President Barack Obama heads to Boston Thursday; first lady Michelle Obama made the trip last month.

Democrats are hoping to avoid a repeat of 2010, when Republican Scott Brown won a special Senate election even though Massachusetts leans heavily Democratic.