Arizona Republican John Shadegg surprised Copper State politicos this afternoon by announcing he will retire at the end of the 110th Congress. First elected in 1994 as part of the Republican Revolution, Shadegg was a staunch conservative who chaired the Republican Study Committee and made an unsuccessful bid for Minority Whip last year.

Shadegg faced what would likely have been a challenging re-election fight against Democratic attorney Bob Lord, though the incumbent would have retained the upper hand. Still, Lord finished the fourth quarter with more than $500,000 in the bank, and given the way Arizona has trended in recent years, he looked likely to give Shadegg a tough fight.

The state's Third District, which encompasses parts of northwest Phoenix and north through Maricopa County, is one of the fastest-growing areas in the country. President Bush took 54% and 58% in 2000 and 2004, respectively, and Shadegg has mostly faced easy elections during his seven terms in office. Last year, though, he dropped below 60% for the first time, and against an opponent he outspent more than eleven to one.

In a statement, Shadegg said the decision to retire was not due to poor fundraising or a political hill too difficult to climb: He raised more money last year than any year previously -- FEC records show he finished 2007 with $860,000 in the bank -- and he referred to polling data showing him ahead of Lord by 31 points, as well as data showing a generic Republican beating a generic Democrat in head-to-head matchups.

Shadegg, who has long been rumored to be eying a Senate seat should John McCain or Jon Kyl step down, left the door open for a future bid. "My health is great; I have not felt better in years, and I expect to be involved in our nation's political discourse for decades to come," he said, per the statement.

Lord will not face an easy race even without Shadegg around. Early speculation about what Republican would run revolved around Sean Noble, Shadegg's chief of staff, who confirmed to Politics Nation that he is "looking very seriously" at a candidacy. Noble had been rumored as a potential candidate in the state's sprawling First District, though he declined to run in that seat.