Presidencies sometimes change course. Trump’s hasn’t so far.

Presidencies sometimes have turning points. Perhaps the starkest one was 16 years ago Monday, when the terror attacks of September 11, 2001, transformed the presidency of George W. Bush. Donald Trump’s time in office has so far been characterized by the absence of such moments, despite major events that seem like they should upend normal political operations.

This is not for lack of effort on the part of some media observers, who desperately wish for some sign that Trump knows where he is or what his job means. The most recent round of this comes in the form of various articles about how Trump’s debt ceiling deal with Democratic leaders means he’s been an independent all along.

But these are the facts on the ground. Trump has enjoyed consistent support from congressional Republicans, and he is unpopular with Democratic elites and voters alike. Is the debt ceiling agreement likely to change this?

Recent presidents besides Bush have had turning points in their presidencies. Bill Clinton’s evolution is harder to pinpoint, but his early White House chaos eventually gave way to a more functional and successful presidency. As for Barack Obama, I think we are still too close to say, though I agree with Jamelle Bouie that Obama’s turning point — almost certainly unintentional — came during a press conference in which he said the Cambridge, Massachusetts, police “acted stupidly” in the arrest of Harvard scholar Henry Louis Gates.

These moments may not have much in common, but it’s clear what they are not: fundamental shifts in the president-party relationship. The 9/11 attacks reordered political priorities and gave purpose to a presidency with an erstwhile meandering agenda. Clinton’s evolution can be likened to a professionalization — to the kind of shift that occurs as a president gains on-the-job training. For Obama, the “beer summit” marks the end of the dream of post-racial America or a transracial presidency (not that the dream was ever very realistic). Presidents can pivot on their priorities, their White House management, or their public image. Often those pivots are at least partially done for them. But the president-party relationship is structural, and harder for presidents to just alter.

As numerous presidency scholars have shown — Richard Skinner, Sidney Milkis, Lara Brown, me — the nuts and bolts of the president-party relationship tend to outlast individual presidencies, reflecting instead the dynamics of nominations, intraparty rules, and power built up over the course of careers. Presidents who have sought to change these dynamics have not done so subtly.

At the same time, it’s hard to deny that Trump’s relationship with Republicans is hardly standard-issue. His path to the presidency highlights the importance of drawing a distinction between parties and partisanship: His primary victory illustrates the weakness of parties to fend off outside challenges like this, including elites’ inability to coordinate. His general election victory was possible because of the power of party loyalty and negative partisanship, which won him strange alliances with many of the same party elites who had just denounced him in the primaries.

Awkward outsiderdom is a typical feature of disjunctive presidencies. Political time is ultimately a theory about the president-party relationship, and one way to address a fraying coalition is to nominate a leader who isn’t identified with any of the warring factions or old icons. Franklin Pierce, Herbert Hoover, and Jimmy Carter all fit this model pretty well. But like Trump, in each of these cases, outsider status is combined with loyalty to some core aspect of the party’s agenda and process.

For Pierce it was the attempt to use the “party machinery” to balance competing concerns in a way that ultimately became removed from the substance of debates over slavery and expansion. For Hoover, this was difficulty moving away from ideas about voluntarism and political economy; for Carter, a focus on institutional reform that centered the executive and neglected Congress and party building was a deep cut back to some FDR themes.

In Trump’s case, as many, many people have pointed out, the connections with orthodox — even extreme — conservative ideology are readily evident. This is perhaps most consistently and notably true when we’re talking about LGBTQ rights protections, which the administration has rolled back, and a constellation of issues that might be described, as FiveThirtyEight’s Perry Bacon Jr. has written, as “white identity politics.”

There are a couple of takeaway points here. First, in an era of strong partisanship and weak parties, we shouldn’t be surprised that the symbolic politics of the administration have been all about core ideology, appealing to the supporters to whom the administration owes its power. But it’s equally unsurprising that Trump’s disagreements with Republican legislators have unfolded as they have: in the course of actual negotiations, where the absent levers of party power allowed Democratic leaders to fill the void, and in an intermittent war of words between Trump and McConnell, where it’s become evident that neither one much fears the consequences of alienating the other.

The impact of past presidential pivots is evident here too. Both Bush’s post-9/11 presidency and Obama’s candidacy offered the promise of new national unity; both ended up contributing to an even deeper polarization over national identity, priorities, and resources. Trump is president because of these political conditions, and he inherits their governing implications. He is deeply indebted to the symbolic commitments of conservatism (and to the conservative media that conveys them), but he owes less to the party itself.

The specific configuration is somewhat unique, but president-party relationships are typically complex, often mostly determined by long-term dynamics. Yet short-term events do sometimes alter the course of a presidency — usually ones beyond the president’s control. This is the most likely source of a fundamental administration shift. There’s a lot about Trump that is distinctive, but if we’ve learned anything in the past year or so, it’s that the usual political forces tend to win out.