WASHINGTON – Even in this anti-Washington political climate, 12-term Democratic Rep. Peter DeFazio had not been on anyone’s endangered list. He generally breezes to re-election in his southwestern Oregon district by 60 percent or better.

But last Tuesday, something curious happened.

A group calling itself Concerned Taxpayers of America started running television spots — a substantial ad buy of $86,000 — contending that DeFazio had been in league with House Speaker Nancy Pelosi, D-Calif., in wrecking the economy. It also touted DeFazio’s Republican opponent Art Robinson as “a new voice, a smarter choice, the independent leader we need.”

Mild fare for an attack ad, but its origin puzzled both DeFazio and his little-known opponent.

“I’m delighted to have their help, but the truth is, I have no idea who is doing this,” said Robinson, a chemist who is popular on the conservative circuit for his work casting doubt that global warming is manmade.

Robinson’s benefactor has spent more on advertising on his behalf than his own campaign has. But there seems to be no record of an organization called Concerned Taxpayers of America, outside a few filings at the Federal Election Commission. The filings list a Capitol Hill address and the name of a treasurer, Republican political consultant Jason Miller.

Miller declined to say who is funding the group. He described the backers only as “folks who are concerned about the direction this country’s economy is going and want to make their voices heard.”

The names behind those voices apparently will remain a mystery — at least until the organization has to make a quarterly filing to the FEC in October.