Former U.S. Attorney Mary Beth Buchanan suffered a thorough defeat at the hands of a newcomer last night in the Republican primary for the 4th Congressional District nomination, losing to her rival in each of the district's six counties.

Ms. Buchanan was defeated by Keith Rothfus, an attorney and former Bush administration official from Edgeworth, in a race to face current U.S. Rep Jason Altmire, D-McCandless, in November. Her upset was the culmination of a surprising campaign characterized by stinging attacks on both sides.

Republican party leaders had for months wooed Ms. Buchanan, of Fox Chapel, to enter the race, believing that her name recognition and fundraising ability would give her a good chance against Mr. Altmire, a two-term incumbent. But Mr. Rothfus, little-known six months ago, gave them more than they bargained for, raising more money than Ms. Buchanan in the lead-up to the primary.

Tuesday night, Mr. Rothfus credited his victory to his grassroots organizing efforts and "nine months of long, hard work."

"We had a message voters responded to -- a citizen legislator from the private sector willing to tackle the big problems ..." he said. "I feel the same frustration they feel, of struggling to support a family, worried about kids and paying for college, or their parents getting sick."

But Ms. Buchanan said Tuesday night that she believed she had been caught up in the anti-incumbent sentiment sweeping the nation, though she was appointed to office, not elected, during her two-decade prosecutorial career.

"There was a very strong sentiment from voters tonight that they wanted to be represented by someone who has not been involved in government and public service," she said.

In internal polling in April, Ms. Buchanan was leading Mr. Rothfus three to one, she said.

Mr. Rothfus doubled Ms. Buchanan's campaign fundraising in April, when she raised a total of $13,400, an anemic amount for a congressional race. That was related to the negative tone of the campaign, she said, but also was affected by supporters waiting to fund her challenge of Mr. Altmire.

Ms. Buchanan had been Western Pennsylvania's top federal prosecutor for eight years, giving her the renown to garner support from many of the tea party movement supporters in Pittsburgh's northern suburbs. But that fame could cut both ways.

On the first day of Ms. Buchanan's campaign, in February, she clashed with a KDKA Radio talk show host over her failed prosecution of former Allegheny County Coroner Dr. Cyril H. Wecht. Mr. Wecht would later host a Democratic fundraiser featuring another of her targets, comedian Tommy Chong.

Last week, she brandished a voter registration printout at a press conference outside the Allegheny County elections office alleging that Mr. Rothfus had been a Democrat through the 1990s, only to find that the data was judged "inconclusive" by the county's elections director.

Mr. Rothfus -- a stomach cancer survivor -- was not shy about battling Ms. Buchanan. His campaign produced an advertisement mocking her radio performance; repeatedly knocked her for working several months last year in the Obama administration; criticized her for writing campaign checks in 2008 for then-Republican Arlen Specter; and derisively compared the voter registration mix-up to the prosecution of Dr. Wecht.

The candidates also warred over their families -- Ms. Buchanan, who has a grown daughter, said she could "devote my full time" to Congress, unlike Mr. Rothfus, who has six school-aged children.

There was plenty of room for personal attacks because the two candidates had few policy differences. Both are anti-abortion, pro-gun Republicans who are against the $787 billion stimulus package and the health care reform bill.

That could presage the Republican challenge of beating Mr. Altmire in November. Mr. Altmire, who also voted against the health care reform bill, has increasingly moved to the right of the Democratic caucus.

The 4th District includes parts of Allegheny, Beaver, Butler, Lawrence, Mercer and Westmoreland counties.

First Published: May 19, 2010, 8:45 a.m.