Trump calls out small 2020 GOP primary field including Joe Walsh, Bill Weld and potential challenger Mark Sanford

WASHINGTON -- President Donald Trump is apparently taking notice of the small field of fellow Republicans challenging -- or contemplating challenging -- him for the GOP nomination in 2020.

In a pair of tweets Tuesday, the president referred to having "Three Stooges running against me."

"One is 'Mr. Appalachian Trail' who was actually in Argentina for bad reasons," Trump continued.

A second tweet reads: "....Another is a one-time BAD Congressman from Illinois who lost in his second term by a landslide, then failed in radio. The third is a man who couldn’t stand up straight while receiving an award. I should be able to take them!"

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His tweets Tuesday night refer to former Rep. Mark Sanford, R-S.C., who appeared on NBC's Meet the Press recently to say he is considering a primary challenge to Trump but who has not yet officially announced he is running for president; to former Rep. Joe Walsh, R-Ill., who announced on Sunday he is running against Trump for the 2020 GOP nomination; and to Bill Weld, a former GOP governor of Massachusetts, who is also challenging Trump in the GOP primaries.

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“Mr. Appalachian Trail” refers to Sanford who admitted in 2009, while governor of South Carolina, to an extramarital affair with a mistress in Argentina after initial reports that he was unavailable because he was hiking the Appalachian Trail. In fact, he had gone to Argentina to visit her, making the phrase "hiking on the Appalachian Trail" a punchline in political circles across the countries at the time and since.

Walsh reportedly said in a Monday night CNN interview that he lost his popular radio show and that he expected that development because nearly "80 to 90%" of his audience supports the president.

"I am running for president. I oppose this president. Most of my listeners support the president," Walsh said. "It's not an easy thing to do to be in conservative talk radio and oppose this president."

Salem Radio Network announced Monday that it was canceling national distribution of Walsh's show effective Sept. 26, according to the Hollywood Reporter.

Walsh has been publicly critical of Trump, including the president's fiscal decision-making and racial rhetoric, despite a history of making controversial and similar statements himself. He has backtracked on many of his own past statements in the past few days, acknowledging he has said "racist things."

“I helped create Trump, there’s no doubt about that,” he said.

As for Weld, the Associated Press reported in 1996 that the then-governor collapsed, fainted and was briefly unconscious during a college commencement where he had been scheduled to speak. Weld had just received an honorary doctorate of law degree when he fell ill which appears to be what Trump is referring to about “receiving an award”.

However, unseating Trump will be no easy feat. The president has the power of incumbency, with nearly 8 in 10 Republicans approving of Trump’s overall job performance in a recent poll, and Trump has brought in $57 million in the second quarter of this year alone, excluding money donated to the Republican National Committee.

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This article originally appeared on USA TODAY: Trump bashes GOP primary challengers including Joe Walsh, Bill Weld