PHOENIX - Arizona House Speaker David Gowan abruptly ended his campaign for the 1st Congressional District seat on Thursday and threw his support to Republican rival Gary Kiehne.

"Our (poll) numbers aren't improving fast enough," Gowan's campaign manager, Constantin Querard, told 12 News. "You don't get points for third."

Gowan's withdrawal comes a week after voters received their mail-in ballots and 19 days before the GOP primary.

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"It takes a great man to do something for the greater good of the country and of the conservative principles that have made this country so great," Kiehne said in a statement issued by Gowan.

Kiehne lost the 2012 Republican primary for the 1st District seat to Andy Tobin by just 400 votes.

Pinal County Sheriff Paul Babeu is the front-runner in the now five-person Republican primary for the seat, representing a large swath of northern and eastern Arizona.

Querard said Babeu had to be stopped.

"He's a disaster for the party," Querard said. "He can't win in the fall."

Babeu, who is gay, has been battered by opponents' questions about his relationship with an undocumented former lover, and his tenure as headmaster at a Massachusetts school for troubled teenagers.

"Our polling shows Sheriff Babeu is very strong in the district and he looks forward to a general election campaign against (Democrat) Tom O'Halleran," said Babeu spokesman Barrett Marson.

Marson said Babeu's polling had shown Gowan consistently pulling less than 2 percent of the vote.

O'Halleran, a former state legislator who in the past has been a registered Republican and independent, is running against Miguel Olivas in the Democratic primary.

The other 1st District GOP candidates are former Secretary of State Ken Bennett; business owner Wendy Rogers; and businessman Shawn Redd.

Gowan, who represents Sierra Vista, still faces an investigation by the Arizona attorney general's office into his spending of taxpayer dollars on his congressional campaign.

A spokeswoman for AG Mark Brnovich said Thursday the investigation was continuing.