McCain Faces Primary Challenger

Arizona senator John McCain, who in recent months has made obstructing the repeal process of "don't ask, don't tell" a political sticking point, beat a conservative Republican challenger in his bid for a fifth Senate term.

Politico called the race for McCain on Tuesday evening over former Republican congressman and radio talk show host J.D. Hayworth. With 19.3% of precincts reporting at 11:30 p.m. Eastern time, McCain led with 58.8% of the vote, compared to 29.8% for Hayworth.

Once considered a fierce conservative challenger, Hayworth, 51, had been outspent by McCain in weeks leading up to the primary. The 2008 Republican presidential nominee spent more than $20 million in the race -- among the most of any politician in an Arizona primary campaign -- compared to $3 million for Hayworth.

McCain, 73, has threatened to filibuster a Senate floor vote on "don't ask, don't tell" repeal, expected next month when Congress returns from its August recess. The repeal measure is attached to the 2011 National Defense Authorization Act, a must-pass appropriations bill.

Other closely watched primary races Tuesday include that of Alaska senator Lisa Murkowski, whose opponent, Fairbanks attorney Joe Miller, received the endorsement of former Alaska governor Sarah Palin. Returns have yet to be reported in the race.