The southwestern state’s 8th congressional district has been so reliably Republican — Trump won it by 21 points in 2016 — that Democrats had barely focused on it since 2012.

Now they are all in, seeking a dramatic upset in Trump country, or at least a close loss, that would push Republicans onto their heels and signal the opposition party could be on its way to ending Trump’s control of Congress.

Two women, Republican state senator Debbie Lesko and Democrat cancer researcher Hiral Tipirneni, are vying for the seat vacated in December by conservative congressman Trent Franks, who quit amid reports he offered a staffer $5 million to be his baby surrogate.

Lesko is slightly favored, but the race is being closely watched for its significance in the broader political trends — and the margin of victory might be just as important as who wins.

“These elections are all about national trends, motivated voters and donors, and omens for November,” government professor John McGlennon of the College of William & Mary told AFP.

“The race has already thrown the Republicans into a panic.”

The GOP has poured money into the contest, in hopes that a stronger-than-expected Lesko victory would reassure skittish Republican donors and leaders that the party has stabilized after some lousy performances.

Winning high-profile elections in Trump country was almost unthinkable for Democrats one year ago.

But after several months of political turmoil in Washington — including sacked or resigning cabinet officials and a swirling investigation over Russia’s election meddling that creeps ever closer to the White House — Democrats are eyeing major gains in November.

Last month Democrat Conor Lamb won a stunning upset over his Republican rival in southwestern Pennsylvania, where another congressman quit amid a sex scandal — and where Trump campaigned twice in a failed effort to keep the congressional seat in Republican hands.

Democrats need to gain 23 seats in the 435-member House of Representatives to retake control of the chamber.

Republicans are meanwhile focused on Arizona’s eighth district as a bulwark that they hope will halt a broader slide.

“If they can hold off the Democrat here by a margin in the high single digits, they may be able to calm the sense of impending doom,” McGlennon said. DM