Arizona House Speaker Andy Tobin has a razor-thin lead over rancher Gary Kiehne for the Republican nomination in the 1st Congressional District.
As of 5:30 p.m. Thursday, Tobin led by 346 votes out of 48,596 votes cast in the race. Some ballots have yet to be counted.
State Rep. Adam Kwasman is in a distant third place. He has said he'll support whoever becomes the Republican nominee.
The winner will face Democratic Rep. Ann Kirkpatrick in the November general election. She already is being targeted by national Republicans in the swing district that runs from Flagstaff to the northern Tucson suburbs.
On Thursday, she challenged her eventual opponent to four debates in the district.
All other congressional races in Tuesday's primary election have been decided.
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