Donald Trump is the president-elect of the United States, and he's got a Republican-controlled House and Senate to pass his every legislative whim.

Except, not really.

The reality is that Trump's unorthodox candidacy included many unorthodox positions for a Republican — positions voters might have eaten up, but that the GOP Congress may be more reluctant to embrace.

And as Trump meets with Republican leaders in Congress on Thursday afternoon, we thought it a good time for a rundown of areas where they might clash:

1. Free trade

Congressional Republicans have generally been very pro-free trade. They've actually been the driving force behind trying to get President Obama's Trans-Pacific Partnership passed; they provided 190 of the 218 votes last year to give Obama “fast-track” authority to negotiate trade deals in hopes of pushing along the TPP. Only 50 House Republicans voted against it.

But Trump has taken a decidedly anti-free trade — and anti-TPP — stance. His election has already led congressional leaders to admit TPP is likely dead, meaning that the clash probably won't happen in public.

But Trump has also said he wants to renegotiate the North American Free Trade Agreement (NAFTA) — a bill that passed in 1992 with more Republican support than Democratic support. He has the authority to do that — and polls show increasing opposition to these trade deals among Republicans — but it's something GOP leaders certainly won't like and could try to fight.

2. Immigration/deportation

This is another issue on which the GOP base is largely with Trump, but GOP leaders and many Republicans in Congress aren't. The fact is that Trump's varying proposals involving extensive deportation have great appeal among many Republican voters, but not among the broader public and not for a party concerned with appealing to Hispanics over the long term.

Support for extensive deportation is generally between 15 and 20 percent in polls, with about three-quarters wanting those who have been here for years to stay, and a majority wanting them to be given a path to citizenship. Support for Trump's border wall is significantly higher, but fiscally conservative Republicans in Congress would also have to find a way to put together the tens of billions of dollars that it would likely cost to build.

And there are still Republicans in Congress who would like to pursue comprehensive immigration reform, including Speaker Paul D. Ryan (R-Wis.). Getting Trump to go along with that priority would be very tough, given his rhetoric on the campaign trail.

3. As much as $1 trillion on infrastructure

Trump said in his last book that U.S. infrastructure requires “a trillion-dollar rebuilding program.” He also said on the campaign trail that he would more than double Clinton's plan to spend $275 billion on infrastructure over five years.

Given that the national debt right now is about $19 trillion and our current federal budget is $3.8 trillion, tacking on another $550 billion to $1 trillion — or about $100 billion to $200 billion annually — is a massive government undertaking. It's the kind that fiscally conservative Republicans will want to make sure is paid for so that it doesn't balloon the debt even more. But finding the money in the budget for anything on that level will be nearly impossible.

Republicans aren't opposed to infrastructure spending, and it's something that both sides generally approve of. But doing it on the scale Trump is talking about will be a pretty tough pill to swallow. There are many examples of big-government ideas that Trump favors that might run into GOP opposition, but this is probably chief among them because of the price tag.

4. No Social Security changes

Let's go to Trump's own words here:

“I'm not going to cut it, and I'm not going to raise ages, and I'm not going to do all of the things that they want to do,” he said earlier this year. “But they want to really cut it, and they want to cut it very substantially — the Republicans — and I'm not going to do that.”

GOP leaders have danced a very delicate dance in recent years when it comes to reforming entitlements. They say they don't want to cut or curtail Social Security benefits — and neither do the vast majority of voters in each party — but they have argued that it's necessary to keep the program solvent. They have proposed creating private accounts and raising the retirement age in the name of making sure the program stays around.

Trump, though, has no time for that. He says he'll make it solvent by improving the economy and cutting “waste, fraud and abuse.” Analysts are dubious. And so any efforts to make basically any changes to Social Security now that Republicans actually have the means to do so will apparently not meet with the approval of President Trump.

5. Glass-Steagall

In a surprise, the Trump campaign was actually able to get a return to the old Glass-Steagall Act inserted into the Republican Party platform this year. The 1933 law was a response to the Great Depression and basically required that commercial and investment banking couldn't take place under the same roof. It was repealed in 1999, and some blame its repeal for the 2008 financial crisis.

But many Republicans in Congress oppose a return to Glass-Steagall, believing it to be an unnecessary burden on the financial sector that makes it more difficult to compete with banks overseas, and that that idea it caused the crises is overblown.

It remains to be seen whether Trump will really press the issue in opposition to business-minded Republicans. While it was a convenient way to draw a contrast with Hillary Clinton's Wall Street ties in the general election, it wasn't a feature of his campaign early on.

6. Russia/NATO

Trump has said he would like to improve relations between the United States and Russia, and Russian President Vladimir Putin said after Tuesday's election that he would like to normalize relations. Trump has also said nice things about Putin and suggested the United States might not defend NATO allies against a Russian incursion unless other countries pay more.

It's not clear what specifically Congress would be called upon to decide when it comes to Russia or NATO, but if Congress is part of the process, you can bet it will be a difficult thing for Republicans to go along with Trump. Putin is broadly unpopular in the United States, and NATO is a diplomatic agreement that GOP leaders find very important.