PORTLAND, Ore. -- U.S. Senate candidate Jeff Merkley has taken out a $250,000 loan against a home he owns in Washington, D.C., to buy television and radio advertising time for his campaign.

So far this election cycle, the Oregon House speaker has raised $1.37 million, compared with the $893,000 raised by Portland lawyer and activist Steve Novick, also vying for the Democratic nomination to challenge Republican incumbent Gordon Smith.

A third Democrat, Eugene real estate broker Candy Neville, has raised less than $1,000.

Smith has raised $8.3 million so far, and has more than $5 million cash on hand.

"Now is the time to reach out to Oregonians before Gordon Smith seeks to distort my record and attack me after the primary," Merkley wrote in a letter to supporters this week.

Merkley's spokesman, Matt Canter, said the campaign wants to take full advantage of the record number of Democrats expected to vote in the May primary that features the presidential race between Hillary Rodham Clinton and Barack Obama.

But Jake Weigler, Novick's campaign manager, said Merkley's loan "raises real questions about Jeff Merkley's viability in this election. Even with all the support of the Democratic establishment in D.C., he now has to borrow money to be able to talk to voters."

Merkley bought the Washington home when he worked at the Pentagon. It is being used as national headquarters for the Lutheran Volunteer Corps.