Sen. Mark Begich (D-Alaska) photographed near University Lake in Anchorage on Jan. 18, 2013. (Marc Lester for The Washington Post)

When you’re in a tough reelection, regional interests will always trump party.

So Sen. Mark Begich’s (D-Alaska) personal attack on Sen. Claire McCaskill (D-Mo.) in a news release Wednesday should come as little surprise, though the party-on-party takedown is a little unusual.

Begich, defending a small-business program for Alaska natives, mocked McCaskill and called her criticism of the program “misguided.”

“I’m afraid my colleague, Senator McCaskill – through her narrow lens as a ‘government oversight and efficiencies guru’ – has trouble understanding Alaska history, even with my repeated attempts to reason with her,” he said.

McCaskill’s office declined to comment. She sent a letter this week to the Small Business Administration asking the agency to investigate a federal contracting program created to help drive business to disadvantaged Alaska native corporations.

A 2010 Washington Post investigation discovered that shareholders of native companies have seen little of the benefits the program promised: “In many cases, the bulk of the money and jobs has gone to nonnative executives, managers, employees and traditional federal contractors in the lower 48 states, a Washington Post examination has found.”

“The story of Alaska native corporations is one of good intentions gone awry — and federal authorities looking the other way because it suited their interests. Both Alaska native shareholders and American taxpayers appear to have been shortchanged by the program, according to The Post’s examination,” colleague Robert O’Harrow Jr. wrote four years ago.

Begich defended the program’s work as “critical,” and said it has been successful. He charged that McCaskill “simply refuses to try and understand the history and culture of a great state like Alaska.”

Begich better hope McCaskill doesn’t ask for her $5,000 contribution to his campaign back.