In April, an Insider poll found that 42% of conservatives were open to considering a GOP primary rival challenging President Donald Trump.

A new Insider poll found that, five months later, that number still hasn't changed. 42% of conservatives have yet to change their minds about a Trump opponent.

Nearly a quarter of conservative respondents said they would "probably" or "absolutely" support a qualified contender.

That's good news for the three candidates who have entered the Republican primary race against Trump.

Business Insider'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.

Visit Business Insider's homepage for more stories.

The vast majority of Republicans think President Donald Trump is doing a great job — Gallup polls consistently place his approval rating among his party at around 90% — but a surprisingly large contingent of conservatives have said they're receptive to a GOP challenger.

In April, an Insider poll found that 42% of conservatives were open to considering a qualified primary contender against Trump. Five months later, we polled again — and the number hasn't changed.

Out of a sample of more than 1,100 American adults, Insider's most recent poll asked non-Democratic-voting respondents about their views on the Republican primary. Here's how those who self-identified as "slightly" to "very" conservative responded:

32% said: "I fully back President Trump and would absolutely not consider voting for any Republican primary challenger." (-1 percentage point since April)

17% said: "I'd probably back President Trump, but I would listen to a qualified primary challenger." (-2 percentage points)

19% said: "I support the president, however I am open to other qualified Republican primary challengers." (+1 percentage point)

10% said: "I would probably support a qualified Republican candidate who challenged President Trump in the primary." (-1 percentage point)

14% said: "I would absolutely support a qualified candidate who challenged President Trump in the Republican primary." (+1 percentage points)

Despite the five months of campaigning that have elapsed between the two polls — which include plans for a social networking app for Trump supporters — hardly anything has swayed the sector of right-leaning Americans who are amenable to the idea of throwing their weight behind another Republican candidate for president.

Nearly a quarter of conservative respondents said they would "probably" or "absolutely" support a qualified contender. That's roughly the same, with a one percentage point increase for those who said they would "absolutely" back a competent adversary.

The Republican presidential primary is finally starting to ramp up, and the polls results might offer hope to the three contenders have entered the race to challenge President Donald Trump: former Gov. Mark Sanford of South Carolina, former Rep. Joe Walsh of Illinois, and former Gov. Bill Weld of Massachusetts.

Trump's allies in the Republican party are already taking measures to thwart opposition, with four states planning to cancel their 2020 GOP primaries or caucuses, meaning that Trump will be guaranteed the party's nomination in those states. The announcements have prompted the three challengers to pen an opinion column in The Washington Post condemning their party for being undemocratic.

None of the contenders come close to rivaling Trump when it comes to name recognition, and no sitting president has lost his party's nomination for a second term since the 19th century. But a strong competitor emerging in the primary has often weakened an incumbent's standing, partly leading them to lose re-election. That reason alone might make it harder for the president to sleep at night.

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.

Read more:

42% of polled Republicans said they're at least open to a GOP challenger to Trump. That's a big problem for the president.

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

Trump will likely survive his primary challenge from Joe Walsh — but history suggests that it could hurt him in the general election

Business Insider'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.