Republicans in South Carolina, Arizona, Kansas and Nevada have already decided not to hold Republican primaries in 2020, opting instead to automatically declare President Donald Trump the winner of the states' delegates.
It is possible more states will decide not to hold GOP primaries.
This comes despite a growing field of challengers gunning to upset Trump during the primary season. They include former Massachusetts Gov. Bill Weld, former governor and Rep. Mark Sanford of South Carolina and former Rep. Joe Walsh of Illinois.
But there is some precedent for this. "As a general rule, when either party has an incumbent president in the White House, there's no rationale to hold a primary," South Carolina GOP Chairman Drew McKissick told Politico.
A number of states, for instance, did not hold Democratic primaries in 2012, although President Barack Obama did not face any organized opposition.
But Weld, Sanford and Walsh could mount the strongest opposition to a sitting president in a primary since 1992, or even 1980. In 1992, Pat Buchanan threatened to defeat President George H.W. Bush in the New Hampshire primary. While Buchanan pulled in 38 percent of the vote in New Hampshire, it was by far his best performance as Bush swept all 50 states to win the nomination.
In 1980, Sen. Ted Kennedy nearly ended President Jimmy Carter's campaign in one of the most competitive primaries in history. Kennedy did not concede until the second day of the Democratic Convention.
Trump dismissed the opposition as a publicity stunt on Monday. He added that he will not debate his Republican challengers.
"They’re all at less than 1 percent. I guess it’s a publicity stunt,” Trump said.
“To be honest, I’m not looking to give them any credibility,” he added.
The odds for Weld, Sanford or Walsh are steep. Trump's current approval rating among Republicans is at 88 percent, according to Gallup .