State-level Republican parties are planning on canceling their primaries and caucuses to benefit President Donald Trump — and Republican voters aren't happy about it.

Former Gov. Bill Weld of Massachusetts, former Rep. Joe Walsh of Illinois, and former Gov. Mark Sanford of South Carolina are all challenging Trump in the 2020 Republican primary.

Politico reported earlier this month that at least four states — Nevada, Arizona, Kansas, and South Carolina — are set to cancel their Republican primaries or caucuses.

Insider polling found that 49% of respondents who self-identified as "slightly, somewhat, or very conservative" disagreed with those states canceling their primaries.

46% of those who "fully back," "would probably back" and "support" Trump also agreed that "Republicans who prefer another candidate than the president deserve a choice to speak their mind."

Business Insider Today's GOP presidential debate will run from 7 PM to 8:30 PM EST on September 24, and will be exclusively live-streamed on Business Insider Today's Facebook Watch page.

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State-level Republican parties are planning on canceling their primaries and caucuses to benefit President Donald Trump — and Republican voters aren't happy about it.

Trump is currently facing three well-known Republican primary challengers. Former Gov. Bill Weld of Massachusetts, former Rep. Joe Walsh of Illinois, and former Gov. Mark Sanford of South Carolina have all jumped in to pose long-shot challenges to Trump's stronghold over the GOP.

Trump currently holds an 88% Gallup approval rating within the Republican party and he already has the backing of the Republican National Committee, which raised a staggering $51 million for Trump's campaign in 2019's second fundraising quarter.

But Politico reported earlier this month that at least four states — Nevada, Arizona, Kansas, and South Carolina — are set to cancel their Republican primaries or caucuses anyway, denying Trump's challengers the chance to earn delegates.

Read more: Trump challengers accuse GOP of rigging 2020 election in the presidents favor by canceling primaries in four states

On September 24, Business Insider Today will be hosting the first-ever 2020 Republican debate between Weld and Walsh, who along with Sanford, recently wrote a joint op-ed in the Washington Post denouncing the primary cancelations as un-democratic.

"In the United States, citizens choose their leaders," they wrote. "The primary nomination process is the only opportunity for Republicans to have a voice in deciding who will represent our party."

Trump and Sanford both declined Business Insider's invitation to the debate.

Insider polled 1,142 Republican primary voters to gauge their views on state-level Republican parties canceling their primaries. (Read more about how Insider polling works here).

Among 353 slightly, somewhat, and very conservative voters:

21% said "I don't agree with the cancellation, I think Republicans who prefer another candidate than the president deserve a chance to vote their mind.

28% agreed that "even if the outcome is assured, it's wrong to cancel primaries and remove the right of Americans to vote."

18% said that "given that the outcome is essentially inevitable, there's no justification for the expense of running a primary."

16% said "President Trump is the head of the Republican party and can do as he sees fit with how the Republican party operates its primaries."

And another 17% said they didn't know.

Read more: How to watch the first-ever 2020 Republican presidential debate

As expected, the vast majority of self-identified Republicans who said they would "probably support" or "absolutely support" a primary challenge to Trump strongly disagreed with state parties canceling their primaries.

But our polling found that even those who support Trump disapprove of GOP voters being denied an opportunity to vote for someone else.

15% of those who "fully back," "would probably back" and "support" Trump agreed that "Republicans who prefer another candidate than the president deserve a choice to speak their mind."

And a full 29% of those who "fully back," "would probably back" and "support" Trump said that "it's wrong to cancel primaries and remove the right of Americans to vote."

20% agreed that "given that the outcome is essentially inevitable, there's no justification for the expense of running a primary."

And 23% said that "President Trump is the head of the Republican party and can do as he sees fit with how the Republican party operates its primaries."

Business Insider Today's GOP presidential debate will run from 7 PM to 8:30 PM EST on September 24, and will be exclusively live-streamed on Business Insider Today's Facebook Watch page.

SurveyMonkey Audience polls from a national sample balanced by census data of age and gender. Respondents are incentivized to complete surveys through charitable contributions. Generally speaking, digital polling tends to skew toward people with access to the internet. Total 1,142 respondents collected September 17 - September 18, 2019, a margin of error plus or minus 2.98 percentage points with a 95% confidence level"