Paul Ryan's primary challenger tore into the House speaker on Wednesday, claiming he's "never cared about his constituents" and wrongfully betrayed Donald Trump.

"It doesn't matter if you're a Republican or a Democrat, it's hard to disagree with the fact that Ryan's efforts to undermine the Republican nominee, whom he pretends to have endorsed, is exactly the kind of two-faced dishonest politics that represents what's wrong with Washington today," Paul Nehlen said during a press conference.

The underdog candidate and local businessman, who trailed Ryan by more than 70 points in May, appeared to make a last-ditch effort to attract voters' attention on Wednesday by lacing into his primary opponent and praising Trump.

"Speaker Ryan's repeated betrayal of Donald Trump is an act of sabotage against our party and an act of sabotage against our Republican electorate who selected Mr. Trump as our nominee," Nehlen said. "Donald Trump has courageously taken on the entrenched special interests who sought to suppress the working people of this country and who have sought to deny them a livable wage. By contrast, Paul Ryan has fought every step of the way to empower those forces working to disenfranchise voters and working to leave our citizens powerless and unable to provide for themselves and their families."

Nehlen encouraged voters to view this election, as well as his upcoming primary on Aug. 9, as a contest between "the American people and the corporate interests who want to rule over us."

"The eyes of the whole nation have turned to Wisconsin's first congressional district," he said. "This race will decide whether our Congress belongs to a collection of special interests and global corporations interested only in themselves, or whether it will belong to the people and families who want only to live in safety, security and peace."

Ryan has "betrayed us on immigration … betrayed us on spending … betrayed us on the budget," Nehlen claimed, describing Ryan as a "soulless globalist ... who is callous to the suffering of the American people."

"He will never change. He will never stand up and fight to protect jobs, security, and wages for Wisconsin voters," he added, calling on "every last voting person" in Wisconsin to cast their ballot against Ryan next week.

Nehlen's sharp jabs at this opponent come 24 hours after Trump declined to endorse Ryan in his primary, telling the Washington Post on Tuesday that he's "not quite there yet."

"Neither Speaker Ryan nor anyone on his team has ever asked for Donald Trump's endorsement," Zack Roday, a spokesman for Ryan's campaign said in reaction. "And we are confident in a victory next week regardless."

Ryan, who himself was slow to endorse Trump, has been a repeat critic of the candidate's national security and immigration proposals. Most recently, he publicly condemned Trump for attacking two Gold Star parents.