Republican State Sen. Steve Smith of Maricopa announced Monday he is running for the 1st Congressional District seat in northern and eastern Arizona, now held by freshman Democratic Congressman Tom O'Halloran.
In an apparent attempt to clear the field of other Republicans, Smith also rolled out endorsements from GOP Congressmen Trent Franks and Andy Biggs.
Smith made his name in the Legislature as an immigration hard-liner who championed the idea of paying for a border wall with private donations.
The fundraising fell far short of its goal. The money was eventually donated to a border county's sheriff's office.
While Democrats have a voter registration advantage in the massive, diverse district, Republicans view it as winnable. GOP presidential nominees have won it narrowly in the last three general elections.
In 2016, President Donald Trump defeated Hillary Clinton in the 1st District by one percentage point.
Yet Arizona Republicans have lost the last three congressional elections there. Last year, O'Halleran defeated Republican Paul Babeu by seven points, bolstered by millions of dollars in outside spending attacking the scandal-plagued sheriff.
Smith, who was first elected to the Arizona House of Representatives in 2010, said he intends to serve out his term through next year's election.