The Republican parties in South Carolina and Nevada announced Saturday that they would not be holding their presidential nominating contests in 2020, and all Republican delegates will be committed to President Trump. They join the Kansas Republican Party, which confirmed on Friday that it will not hold its caucuses in 2020.

States have until October to submit their delegate selection rules to the Republican National Committee, and several more state Republican parties could vote to cancel their nominating contests before the deadline.

The move is not unprecedented for incumbent parties. In 2004, ten states cancelled their nominating contests to support President George W. Bush.

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In many cases, the state party has to pay to hold its primaries or caucuses. So if there is an incumbent with considerable support, then the party is inclined not to incur the costs of putting on an expensive primary. According to a Nevada GOP spokesperson, the state party would save nearly $150,000 if it cancels the caucuses for the 2020 cycle.

Chairwoman Ronna McDaniel told CBS News last week that the Republican National Committee does not dictate whether the state parties should hold nominating contests. That decision is left to the states. However, Mr. Trump's re-election campaign has dispatched its delegate staff to many of the GOP state conventions where they have observed chair elections and advised on delegate selection rules.

The longshot Republican challengers to Mr. Trump have voiced concern over the process.

Former Congressman Joe Walsh's presidential campaign sent letters to all four early-voting states requesting instructions for ballot access, and in a tweet this week Walsh said cancelling primaries "is what a political party does when it serves a King."

Bill Weld in May told CBS News that he was not having discussions with the state parties.

"Why would I talk to the state parties?" Weld responded when asked if he was trying to get ballot access in early-voting states. He added, "They're all run by Trump people."

Former Congressman Mark Sanford from South Carolina has also considered challenging President Trump but has delayed any announcement until after Hurricane Dorian passes.

Mr. Trump may have some challengers but his approval rating among Republicans is still high — 88 percent — according to recent polling by Gallup.