The Republican Party is not splintering over Trump
Much has been said of the Republican Party not being unified or being fractured in the age of Donald Trump, but I maintain these divisions are overblown. Certainly, divisions do exist. But divisions within the Republican Party (and the Democratic Party) have always existed and will always exist. In broad strokes, Republicans are unified - especially on policy. Let's look at a few of those areas:
Taxes: Broadly, Republicans agree that tax rates should be lowered and that the tax code should be streamlined and simplified. There are some Republicans who think the plan does not go far enough and want the top rates slashed (I am raising my hand) but there is broad unity on this issue.
Immigration: This is probably the biggest policy difference between populists and the establishment. (I tend to be more pro-immigration.) However, the party's base for the most part is closer to Trump than the Republican Party establishment. This is not corruption or "the swamp" but a different opinion on policy.
Government regulations: Reversing burdensome regulations implemented administratively by Barack Obama was a big focus of the first few months of the Trump administration, and that is actually one of the big reasons I warmed up to the President. There is wide agreement among all of the various factions of the Republican Party (libertarians, business interests, populists and the religious right) on this issue.
Abortion: Most Republicans agree with more limits on abortion, and especially on reversing the ObamaCare mandate on birth control coverage. Republicans in the states have been actively working to limit abortion, and Indiana saw an 8% drop in abortions from 2015 to 2016.
Ben Shapiro noted that with the lack of policy differences, the primary difference between the Republican establishment and the populists is attitude.
Donald Trump is brash and loud and the establishment is horrified by that. I have been where Trump is now: Attacked by my own allies for being too harsh with Democrats and Leftists. That is why, while I have been critical of Trump's style, I understand where he is coming from. I understand why the populist base loves him for being a brawler. The establishment can learn a lot from Trump in this regard, especially his instinct to punch back when attacked. In fact, it was the establishment's lack of willingness to confront Obama that created Trump and the populist uprising that supported Trump.