Nevada and South Carolina GOP cancel 2020 presidential nominating contests Arizona and Kansas are finalizing plans to opt out of primaries and caucuses.

Republican officials in South Carolina and Nevada voted Saturday to cancel their nominating contests in 2020, prompting President Donald Trump's long-shot primary opponents to rail against the stunning but not unprecedented move.

The votes, which come as Kansas and Arizona are also finalizing plans to forgo their GOP presidential primaries and caucuses, follows a broad effort by the Republican National Committee to give "undivided support" to the president - even passing an unprecedented loyalty pledge earlier this year before he's the party's official nominee.

"With no legitimate primary challenger and President Trump's record of results, the decision was made to save South Carolina taxpayers over $1.2 million and forgo an unnecessary primary,” Drew McKissick, the chairman of the South Carolina GOP, said in a statement. "President Trump and his administration have delivered for South Carolinians, and we look forward to ensuring that Republican candidates up and down the ballot are elected in 2020."

Late Saturday, the Nevada GOP voted to opt out of its caucus process, but the state party stopped short of nominating Trump. Instead, state party officials on the central committee will participate in an endorsement vote, which could bind the state's delegates to the president, at a later date.

"As the chairman of the Nevada Republican Party, my job is to ensure not only President Trump’s victory in Nevada but also to elect more Republicans down the ballot. It would be malpractice on my part to waste money on a caucus to come to the inevitable conclusion that President Trump will be getting all our delegates in Charlotte," said Chairman Michael J. McDonald. "I am excited that our central committee has agreed with this proposal and voted to give us a way to bypass the caucus process."

Meanwhile, the Kansas Republican Party told ABC News on Friday that it is not planning for a caucus. Arizona is expected to make a decision later this month.

"It’s utter bulls---," former Rep. Joe Walsh, R-Ill., who launched a primary challenge during an exclusive interview on "This Week," told ABC News in an interview done Friday. "It’s undemocratic. It’s what a mob boss would do and that’s how Trump’s behaving right now."

Politico first reported on states' plans to drop the primaries.

Walsh blamed the president - even likening Trump to a king - and signaled his openness to legal action to fight back against the four states that are opting to forgo the primary process.

"This can’t—This can’t happen in America," he said. "Donald Trump is not a king. You cannot just eliminate elections. We are going to fight it in these four states. If they proceed and do this we are going to fight them with everything we've got legally."

"We're pursuing legal avenues to fight this," he added.

Former Massachusetts Gov. Bill Weld, who declared earlier this year that he's running against Trump, struck a similar tone, saying the president "wishes to be crowned" instead of being "elected."

"Donald Trump, by turns arrogant and paranoid, has made no secret of the fact that he wishes to be crowned as President rather than elected," he told ABC News. "That might be fine in a monarchy, but we overthrew ours two centuries ago. The fact is that Mr. Trump and his handlers are keen to bypass the basic procedures of democracy as far as they can, because they know how awful he will look alongside candidates who are intelligent, experienced, and decent."

But an RNC official argued that shutting down primaries and caucuses is not new during an incumbent's re-election campaign. The official pointed to Republicans canceling eight primary contests in 1992 and 10 in 2004, and Democrats scrapping eight primaries and caucuses in 1996 and 10 in 2012, during former President Obama's re-election campaign.

"Republicans and Democrats alike have opted out ... in previous election cycles: Democrats did so in 1996 with then-incumbent President Bill Clinton, and again in 2012 when President Obama was in office; Republicans opted out in 2004 when President Bush was up for re-election," said Republican Party of Arizona Chairman Kelli Ward. "This is nothing new, despite the media's inauthentic attempt to portray it as such. Arizona Republicans are fired up to re-elect President Trump to a second term and will continue to work together to keep America—and Arizona—great."

The Arizona GOP will be weighing its decision at their upcoming quarterly executive committee meeting on Sept. 14, with one official telling ABC News, "it's likely" the primary will be canceled.

Arizona's Secretary of State's office confirmed that the Democratic Party did not participate in the presidential preference election in 1996 and 2012. But a spokesperson for the state Democratic Party told ABC News that it did hold caucuses during both Obama's and Clinton's re-election. In 2012, as the only candidate on the ballot, Obama received all 70 pledged delegates in the caucuses.

"Whether or not to hold a presidential primary is a decision made by our state executive committee every four years. There is strong precedent on the part of both parties to not hold a primary when they control the White House," said South Carolina GOP Chairman Drew McKissick.

The Kansas GOP confirmed Friday it would not organize a caucus in 2020.

"The Kansas Republican Party will not organize a caucus for the 2020 election because President Trump is an elected incumbent from the Republican Party," said Shannon Golden, executive director of the Kansas Republican Party. "Every time an incumbent Republican has run for re-election, except in 1912 (when they went for Roosevelt instead of Taft), the Kansas Republican Party state convention adopted a resolution instructing all delegates to vote for the elected incumbent."

The RNC official also noted that state parties incur fees to pay for a primary or caucus, which is a big factor as they consider this decision. In Kansas, GOP Chairman Michael Kuckelman estimates it would cost the state party $250,000 to hold the caucus, money that could be used elsewhere, including to compete in tight races.

But two other early nominating states - Iowa and New Hampshire - are adamant that the decision to abandon the voting process in these states will not change anything for them.

The Iowa GOP told ABC News that their caucuses will continue as planned.

In New Hampshire, the secretary of state, a Democrat -- and not the state GOP -- runs the primary. Still, the spokesperson for the state Republican Party told ABC News: "Regardless of what other states do, New Hampshire's primary will always be the first in the nation."