Traditional Republicans fancying the cracks in their party as an opening to primary President Trump in 2020 need to deal with one inconvenient fact: Republican voters aren't interested.

The brawl for dominance in the Republican Party is certainly remarkable. Former President George W. Bush; Ohio Gov. John Kasich; the chairmen of two top Senate committees; and now Sen. Jeff Flake, R-Ariz.; all have sharply rebuked Trump, questioning his fitness, integrity, and moral authority.

But their resistance, though hardly isolated, is missing one crucial element: a significant measure of enthusiasm from Republican voters. That's a weak foundation from which to pursue a challenge to the renomination of a sitting president.

"You've got to understand the turf you're fighting on," said Rep. Steve Stivers of Ohio, chairman of the National Republican Congressional Committee, the House GOP campaign arm.

"Some of the members [of Congress] who've been picking petty battles with the president have done it on issues that aren't really things that our voters are with them on," Stivers added. "That matters."

In Arizona, Flake was essentially forced into retirement because his opposition to Trump was rejected. The senator didn't endorse the president in 2016, raising the volume on his concerns about Trump's leadership since the inauguration. It soured his relationship with Republican voters and didn't to anything to help his general election prospects, either.

Nationally, Trump has maintained his standing with Republican voters through myriad controversies and legislative failures, receiving a job approval rating of anywhere from the mid-80s to low 90s. Contrast that with his dismal, average national approval rating of around 40 percent.

That is attributable partly to anger at Washington and disgust with Congress. But there also appears to be a disconnect between the traditional wing of the Republican Party and the GOP voting coalition, and how each views Trump.

"We must stop pretending that the degradation of our politics and the conduct of some in our executive branch are normal. They are not normal," Flake said in a stunning denouncement of Trump from the Senate floor. "Reckless, outrageous, and undignified behavior has become excused and countenanced as 'telling it like it is,' when it is actually just reckless, outrageous, and undignified."

"When such behavior emanates from the top of our government, it is something else: It is dangerous to a democracy," Flake added. His comments came just hours after Sen. Bob Corker, R-Tenn., chairman of the Foreign Relations Committee, called Trump a liar and said he "debases" the country and just days after Bush warned against isolationism and "nationalism distorted into nativism."

But where Trump's Republican opposition sees a dangerous political provocateur, the GOP base sees a fighter who is defending them and their values — against the cultural oppression of the liberal elites in New York and Hollywood and against a political establishment in Washington that bends the rules for everyone but them.

And, where Trump's Republican opposition sees a radical nationalist who threatens the American melting pot at home and the abdication of U.S. leadership abroad, the GOP rank and file, including some skeptical of Trump, see a jobs-focused president pursuing a largely traditional GOP domestic and foreign policy agenda.

The Republican civil war is real. The institutions that make up the party, from Congress to think tanks to prominent members of the conservative media, continue to resist Trump's populist strain of Republicanism and his takeover of the party.

But for the most part, the voters that empower those institutions feel differently. To be sure, some Republican voters would prefer that Trump calm his Twitter habit and act more presidential. Eventually, their patience could run out. But for the most part, the president is giving Republican voters what they want. In that sense, Trump has already won.

"The politicians who are meeting the market are being rewarded with votes. Until the market changes, we can expect to see more of the same behaviors and more of the same winners," Republican strategist Bruce Haynes said.