The latest Republican plan to repeal and replace the Affordable Care Act has been touch and go for months now. Many are asking why Republicans have had such trouble delivering, even with control of the House, Senate, and the White House. President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE lays blame primarily at the hands of Democrats. However, research I conducted as part of the Democracy Fund Voter Study Group on the 2016 election finds that the president’s fractured coalition is largely responsible.

A statistical analysis of an 8,000 person survey uncovered five different types of Trump voters. These voters disagree on nearly every major policy issue surveyed — including on health care, taxes, immigration, race, and matters of American identity. These internal disagreements help to explain why the Trump agenda is having a difficult time in Congress even as 82 percent of Republicans remain behind him.

One group of Trump backers, whom I call American Preservationists, comprise Trump’s core base of supporters who propelled him through the primaries. They have lower incomes and education and are underemployed. Nearly half of those working age are on Medicaid. Out of step with Republican orthodoxy, Preservationists favor tax hikes on the wealthy, are deeply skeptical of immigration — both legal and illegal — and overwhelmingly support a temporary ban on Muslim immigration. They also feel less favorable toward immigrants and racial minorities, and nearly half think being of European descent is important for being truly American.

Free Marketeers are 25 percent of Trump’s backers and they are the mirror image of American Preservationists, having the highest incomes and education levels. They are most skeptical of Trump, with most saying they voted against Hillary Clinton Hillary Diane Rodham ClintonWhat Senate Republicans have said about election-year Supreme Court vacancies Bipartisan praise pours in after Ginsburg's death Trump carries on with rally, unaware of Ginsburg's death MORE rather than for Trump. In contrast to the Preservationists, these are small government fiscal conservatives who embrace free trade. At the same time, they are as likely as Democrats to have warm feelings toward immigrants and racial minorities, and to support making legal immigration easier.

The largest Trump voter group is the Staunch Conservatives. They are 31 percent of his support and were the group that combined with the American Preservationists to give Trump the Republican nomination. They are loyal Republicans with conventionally conservative positions on social and economic issues. They also have warm feelings toward racial minorities in the U.S. However, although not as hardline as the Preservationists, they too are skeptical of immigration and strongly support a temporary travel ban on Muslims traveling to the U.S.

Had Anti-Elites, 19 percent of his voters, not turned against Hillary Clinton, Donald Trump may have lost the presidency. About half had positive views toward Clinton just four years ago. They support a more progressive tax code, a plurality support a pathway to citizenship for unauthorized immigrants, and they are as favorable toward racial minorities as non-Trump voters. Why aren’t the Anti-Elites Democrats? In addition to sharing Trump’s disdain for elites, they soured significantly on Hillary between 2012 and 2016 and are more cautious of immigration than Clinton.

Finally, the Disengaged (5 percent) is a small Trump voter group. They don’t know much about politics but what they do know is they are skeptical of immigration and believe the system is rigged against them.

Recognizing Trump’s diverse coalition helps explain why Republicans are having difficulty governing in Washington today.

The health care debate is a good example. Nearly 100 percent of Staunch Conservatives and Free Marketeers agree it is not government’s responsibility to guarantee universal health insurance — twice as likely as Preservationists and Anti-Elites.

Although Trump’s voters agree the Affordable Care Act should be repealed, polls reveal continued disagreement over replacement. For instance, an Economist/YouGov poll found that half of Trump’s voters think the health care system needs to be completely rebuilt, while the remainder think reforming the existing system will do the trick. Similarly a Washington Post/ABC news poll found his voters are divided on whether it’s more important to provide health insurance to low income people or cut taxes.

With health care reform on the ropes, there is added pressure for the Republicans to deliver a victory on taxes this fall. However, Trump’s fractured coalition may thwart it. For instance, nearly three-fourths of Preservationists and Anti-Elites favor tax hikes on the rich. Yet Staunch Conservatives and Free Marketeers oppose this policy by the same margins. Or when it comes to the border-adjustment tax, 62 percent of Free Marketeers favor policies that increase trade with other nations, while only a little over a third of Preservationists agree.

In short, Trump voters do not share a similar panoply of policy preferences. Trump earned their votes for different reasons and they have different expectations in mind for his presidency. Without the cohesive coalition that many have assumed, Trump will continue to find it difficult to deliver on all of his promises.

Emily Ekins Ph.D. is a research fellow and director of polling at the Cato Institute, a libertarian think tank. Follow her on Twitter @emilyekins.

The views expressed by contributors are their own and not the views of The Hill.