Donald Trump gave an important and revealing speech in Pennsylvania this week, although the significance may have been less what he said and more who said it with him.

The subject was Obamacare and the supposed havoc that the program is wreaking upon America. Both Trump and vice presidential nominee Mike Pence spoke ― making it one of the few times in this campaign the two have appeared together. Even more telling, however, was the appearance of a half-dozen Republicans from Congress, including Sen. John Barrasso from Wyoming and Rep. Tom Price from Georgia, all talking about the same subject.

Progressives should take note. Trump has spent a lot of time criticizing Republican leaders in Congress, and they have spent a lot of time criticizing him ― on everything from his treatment of women to his pronouncements about Muslims. Trump also deviates from the GOP party line on a few key issues. Most notably, his hostility to international trade agreements puts him at odds with Republican leadership and its backers in the corporate community.

These differences make it easy to assume that if Trump became president, he and the Republicans in Congress would be at loggerheads ― that his deviations from normal conservative orthodoxy, to say nothing of his deviations from normal adult behavior, would make him an unreliable and ultimately unproductive governing partner.

But this would be serious mistake. The truth is that Trump and the Republicans agree far more than they disagree. He wants to get rid of the financial industry reforms known as Dodd-Frank. They want to get rid of Dodd-Frank. He wants to ramp up defense spending. They want to ramp up defense spending. You get the idea.

Yes, there are issues in which Trump’s conservative convictions seem shallow, or non-existent. In 1999, he described himself as “very pro-choice.” And just last year, he stumbled through a question, during an MSNBC interview, that suggested he hadn’t really thought through the abortion issue.

But on most major domestic policy issues, Trump and the Republicans hold nearly the same position.

A Hoax Perpetrated By The Chinese

Look at climate change ― quite plausibly the most important issue in the campaign, given that the future of the planet is at stake.

Trump got a lot of grief for saying that he thinks climate change is a hoax, perpetrated by the Chinese. But those kind of far-out views are par for the course in the House and Senate Republican caucuses. Remember, this is a group who handed control of the Senate Environment and Public Works Committee over to Jim Inhofe of Oklahoma, who wrote a book called The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future and once brought a snowball to the Senate floor because he said it showed that climate change isn’t real.

As president, Trump wouldn’t need much help to stop ― and then start to reverse ― the enormous progress on climate change that the U.S. has made under President Barack Obama. Trump has already promised to back out of the newly signed Paris treaty on reducing greenhouse gases, a milestone but delicate international agreement under which the U.S. has committed to hitting targets for lower emissions. Trump could also stop the Obama administration’s new rules for power plants from taking effect ― or sign a bill from Congress rescinding them legislatively.

Even if Trump were to stop short of these dramatic steps, he could use his appointments and leeway over regulations to slow down and eventually halt implementation of domestic efforts to reduce greenhouse gases. Republicans on Capitol Hill would cheer this, if their past statements are indicative.

Tax Cuts For The Wealthy

Another clear instance of Trump-Republican synchronicity is tax policy.

Trump has issued no less than three separate tax cut proposals since the start of his campaign, and if you count the changing descriptions of them he’s made, there have been even more than that. This inconsistency makes it easy to think he doesn’t have a fixed idea about what he’d do ― easy, but wrong. The basic concept of what he wants to do has never changed. For all of his bluster, he is, on taxes, an extremely traditional Republican.

In fact, the most recent version of his proposal ― the one he issued in September ― looks quite a lot like one floated by House Speaker Paul Ryan earlier this year. Both would slash the top income tax rate from 39.6 percent to 33 percent. Both would reduce taxes on corporations, in largely similar ways.

Under both schemes, the wealthy would gain disproportionately. In Trump’s plan, according to Citizens for Tax Justice, 44 percent of the tax cut benefits would go to the wealthiest 1 percent of the population ― or maybe more, depending on a few details Trump didn’t make clear.

Keep in mind that the the distributional projections about tax cut proposals understate their impact in a critical respect. A tax cut that reduces federal revenue by somewhere between $4 trillion trillion and $7 trillion over 10 years, as pretty much everybody agrees both the Ryan and Trump tax cuts would, is going to affect the future of federal spending. The likely long-term effect will be at least some cuts to programs on which the poor and middle class depend more than the rich.

Personality, Not Policy

And then, as always, there is Obamacare. Neither Trump nor Republicans in Congress have been specific about their plans for health care. But both Trump and the Republicans have talked about the same basic concepts ― scaling back the Affordable Care Act’s new requirements on insurers, transforming its subsidies into more regressive tax breaks, and transforming Medicaid into a program with fewer rules and less money.

A Commonwealth Fund analysis, produced by two researchers at the RAND Corporation, found that Trump’s proposal would result in somewhere between 16 million and 25 million fewer insured. It’s a very rough guess, based on what they could glean about Trump’s plan from the sketchy campaign outline. And it’s always possible that, confronted with the real tradeoffs of policy, both Trump and the Republicans would opt for less severe changes. But Obamacare has been such a focus of their rhetoric, for so long, they would feel obligated to do something significant -- and the likely result is going to be some combination of fewer people with insurance, less generous coverage, or some mishmash of the two

The primary focus of the presidential campaign hasn’t been policy, obviously. It’s been personality. And that’s entirely appropriate, given how dangerous and unstable Trump could be as president. It’s the reason why so many influential conservatives ― like Ross Douthat and David Frum and Jennifer Rubin ― refuse to support him, even though, on most policy areas, they have a lot more in common with him than they do with Hillary Clinton.

The conservatives elected to Congress, as part of the Republican Party, are a different story. By and large, they have fallen in line behind Trump’s candidacy, despite all but admitting he is unfit for office. Partly it’s because they fear a backlash from Trump’s voters, but partly it’s because they realize that a Trump presidency would give them a chance to write legislation almost at will.

They have spent the last six years crafting their plans. All they have lacked is a president who thinks they like they do. And in Trump, it appears, they would finally have one.

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims — 1.6 billion members of an entire religion — from entering the U.S.