President Trump’s firing of White House Chief Strategist Steve Bannon is the latest in a string of major administration departures over the last month. But unlike others who left (Reince Priebus, Anthony Scaramucci and Sean Spicer), Bannon was a clear fan of Trump since the primary campaign. Indeed, Bannon’s website, Breitbart.com, was instrumental in supporting Trump long before any members of the Republican establishment got behind him.

After Bannon was fired, he said he was going to “war” against the president’s enemies, including some in the administration itself. Bannon, moreover, represented a clear ideological wing within the Trump White House and in the GOP electorate more broadly. If Bannon wages a media campaign against Trump, or if Bannon’s departure leads the White House to turn away from Bannon’s nationalist agenda, how much political trouble could Trump have? Put another way: How big is the Bannon wing of Trump’s coalition?

They don’t make up a majority, but a big chunk of Trump’s voters share Bannon’s positions.

Before we delve into the numbers, let’s first define what we mean by the “Bannon wing.” Generally, we’re talking about a more populist, nationalist and isolationist brand of Republicanism. More specifically, Trump voters who are pro-police, against free trade, against the U.S. playing an active role (militarily and diplomatically) in the international community, strongly against illegal immigration, and in favor of more infrastructure spending. There are obviously other parts of Bannon’s agenda, but these are among the defining features that help separate it from other wings within the Republican Party.

To help us figure out how many Trump voters match this description, let’s consult the 2016 Cooperative Congressional Election Study. The survey asks voters whether …

They are for or against the Trans-Pacific Partnership. (Which we’ll use as a proxy for free trade.) The U.S. should send troops to help the United Nations uphold international law. (Involvement in the international community.) The U.S. government should identify and deport immigrants in the country illegally. (Illegal immigration.) Their local police should receive a grade of A (excellent), B (above average), C (average), D (below average) or F (poor). Their state government should increase spending on infrastructure. (Infrastructure spending.)

Among Trump voters, approximately 15 percent supported all five positions, including a B or better for their local police. So let’s call this 15 percent the “core Bannon” voter. This isn’t a particularly large group. On its own, for example, it’s not enough to win a Republican primary. But it’s certainly big enough that Trump needs its continued support in order to survive a serious primary challenge in 2020 (if one arises). Remember Trump won only 45 percent of the national primary vote in 2016. To put this 15 percent in some additional perspective, the percentage of Hillary Clinton voters who were Hispanic in the general election, an important part of her coalition, was about 12 percent.

Of course, there are members of Trump’s coalition who agree with some of what the Bannon wing believes, but not all of it. And these issues don’t all rank as equal priorities for all Trump’s voters. So let’s expand the possibilities a bit and make for looser ideological groupings:

Isolationist Bannon-ites — Trump voters who want the U.S. to have a more distant relationship with international partners. These are people who are against the Trans-Pacific Partnership and against sending troops overseas to uphold international law. Nationalist Bannon-ites — Trump voters who support deporting immigrants who are here illegally. These voters are pro-police and strongly against illegal immigration. You might also call these voters cultural conservatives. This group’s policy preferences overlap with the white nationalism often voiced at Bannon’s website, Breitbart, but it’s a much bigger group. Populist Bannon-ites — Trump voters who are more economically populist in a party that often isn’t. These voters are against the Trans-Pacific partnership and are for more infrastructure spending.

Clearly, there is going to be some overlap between these groups. There will be some who fit into just one of them, some two and the aforementioned 15 percent who agree with all three. Individually, each of these three groupings has a lot more support than the five-for-five Bannon wing.

About 50 percent of all Trump voters fall into Group No. 1 — they want the U.S. to be less active on the world stage. The pull of this group shouldn’t be too surprising given that even Clinton was forced to come out against the Trans-Pacific Partnership, and Trump made a point during the primary campaign of (falsely) claiming that he always opposed the Iraq War.

Group No. 2, nationalist Bannon-ites, make up about 45 percent of Trump voters, people who want to identify and deport all immigrants in the country illegally and give their local police a grade of above average or better. Trump’s appeal clearly went beyond voters with hardline positions on policing and immigration — issues that represented the starkest contrast with Clinton. But cultural conservatives are a substantial portion of Trump’s coalition.

The smallest group is the economic populists. About 40 percent of Trump voters were against the Trans-Pacific Partnership and for more infrastructure spending. This may be the area where Bannon and Trump were most at odds with Republican Party leaders. Sure, there were Republicans who had been arguing against free trade for a while (see Pat Buchanan), but few Republicans argue for more infrastructure spending. The departure of Bannon from the White House is another sign that the infrastructure part of the Trump agenda is seriously imperiled.

Perhaps the most telling sign that Bannon’s positions represent a major part of the modern Republican Party is the percentage of Trump voters who disagree with all of the five key Bannon-esque policy stances listed above. It’s less than 2 percent. Whether the Republican mainstream likes it or not, a little bit of Bannonism is in pretty much every Republican voter. Don’t expect Trump to suddenly become a different person. Bannonism is a part of Trump’s coalition, even if Bannon is no longer part of the Trump administration. And Trump needs it to remain that way.