Joe Walsh is charging President Trump with fumbling border security, a move for the jugular as the conservative former Illinois congressman begins his long-shot bid to unseat the populist commander in chief in the 2020 Republican primary.

As a concerned Trump moves urgently to deliver on his signature issue, Walsh told the Washington Examiner that he is an honest, effective alternative who is equipped to resolve the immigration crisis. Indeed, the ex-lawmaker, known for a sharp tongue that can be as acerbic as Trump’s, claims the president is making matters worse.

Not only are the measures Trump favors exacerbating the challenge of securing the southern border, Walsh said, the president’s habit of demonizing immigrants from Mexico and Central America, both legal and illegal, is driving key voters into the arms of a Democratic Party that is far less committed to halting unauthorized entries into the U.S.

“Absolute incompetence” is how Walsh describes Trump’s border security policies and attempts to reduce illegal immigration. “Trump’s a one-trick pony about the border. All he talked about was the wall, the wall, the wall, and Mexico’s going to pay for it. There was no nimbleness beyond the wall,” he said, adding that the president is ruining the reputations of true “border hawks” such as himself.

“So many of the things that I believe in, Donald Trump has taken to dark, ugly places,” Walsh said. “Trump’s taken that whole issue of the border and he’s turned it into a kind of, ugly, bigoted, ‘go back to where you came from’ kind of a thing. So, I’m a conservative, and if there’s one area that I’ve changed on in the past couple of years, and it’s because of Trump, I’ve changed my tone.”

Walsh, 57, was a member of the 2010 class of Tea Party Republicans that helped the GOP win control of the House of Representatives in a historic swing.

His tenure representing a Chicago-area district was cut short in part by redistricting — Walsh’s seat was carved up and he lost his bid for a second term running against now-Sen. Tammy Duckworth in the suburban district she represented at the time. But Walsh was memorable, making a name for himself by hurling insults at Barack Obama and other opponents, verbally and on Twitter, that years later would become a staple of Republicans like Trump.

After losing in 2012, Walsh took his act to talk radio, a good fit for his politically charged commentary. That began to change in 2017, as Walsh grew increasingly frustrated with Trump. The former congressman found himself unhappy with the president’s foreign policy, trade policy, seeming indifference to the burgeoning federal debt, and, above all, what Walsh claims is Trump’s habitual lying. The change of heart did not go over well with his pro-Trump audience.

“In my business, conservative media, there are two kinds of people. There are the kinds of people like the Sean Hannitys, who are his absolute sycophants,” Walsh said. The other kind, he suggested, are people like him.

“Right now, the audience is pro-pro-pro-Trump, so they want to hear pro-pro-Trump stuff. I couldn’t do that because I can only say what I believe. So, as I began to go south on Trump, again just consistently saying what I believe for better or for worse, the reaction from my listeners would get more harsh and harsh, and it didn’t go well. It’s a difficult medium for someone like me.”

Walsh is not the first Republican to primary Trump. Bill Weld has been running since spring. But unlike Weld, who spends most of his time in New Hampshire, host of the second nominating contest on the primary calendar, Walsh is vowing to campaign there and other 2020 battlegrounds — beginning immediately.

Walsh, who is consulting with prominent Never Trump Republicans, declined to reveal how much money he has raised, but said money is flowing in and that he’s hired nearly a half-dozen staff, with more on tap. He is working on ballot access, a potentially arduous legal process, but is vowing to be on the ballot in every state that holds a GOP primary.

Trump enjoys sky-high approval ratings with Republican voters and has been assembling a formidable, billion-dollar machine with the full backing of the GOP infrastructure. Even if Walsh manages to mount a credible campaign, his prospects appear dim. But the challenger, apparently undaunted, is betting that there is a secret hunger for a Republican willing to say publicly about Trump what they only think quietly to themselves.

“I think it’s important that Donald Trump is getting pounded every day,” Walsh said. “This campaign is a referendum on him and his fitness.”