For the many Americans who either hate or love Donald Trump, judging the effectiveness of his White House performance—as distinct from merely reacting to it—will be a challenge. But both opponents and supporters owe it to themselves to consider the question somewhat objectively, if only so they can better understand what's going on in the next few years.

An important guideline in evaluating any president is the distinction between the two quite different sides of the office, the “two presidencies” analysis credited to political scientist Aaron Wildavsky. The president can, of course, act more freely in foreign policy, which mostly doesn't require legislation and therefore is less limited by congressional opposition. (For this reason, Wildavsky noted, presidents tend to be drawn disproportionately toward foreign policy activity, whatever that might mean concretely to a particular president.) Furthermore, foreign policy expectations among Trump's voters, and others, are not especially high. Many Americans will consider him successful enough in foreign affairs if “the world” doesn't seem to get worse.

In domestic policy, though, President Trump faces high congressional hurdles due not only to the presence of 48 Democrats (nearly all of them, so far, essentially uncooperative with him) in the Senate, but also to House Republicans' reasonable fear of losing their majority in the 2018 election. It is hard to see how Obamacare as a whole will be repealed and replaced, because of the issue's complexity and its great personal relevance to so many Americans—a situation that makes it very difficult to satisfy all congressional Republicans, whether in policy terms or in terms of their political self-interest. It also seems doubtful that Trump will succeed in enacting major tax cuts or building a wall on the border.

It isn't even safe to assume that effectiveness in the sense of getting things out of Congress will always help him politically. Tax cuts weren't at the heart of his campaign, and they wouldn't necessarily be a net political benefit to him unless key groups of voters think they have improved the economy for average Americans—which depends on the economy's unpredictable performance and especially on more jobs, which Trump conspicuously promised. A border wall, or major steps toward one, would please most of his backers but could also spark even more anger, and thus motivation, than ever among the anti-Trump base. Repeal of Obamacare, no matter what it's replaced with, might well make the president even less popular than he is.

On the other hand, a lack of legislative results in major domestic policy would leave him vulnerable to a charge from disgruntled supporters that he “hasn't done anything.” They already see Washington, not altogether wrongly, as a place where little change is made. For Trump to be coupled in many of their minds with that situation, following an insurgent campaign in which he blasted Washington and made such grandiose promises, could be fatal.

In judging Trump's domestic effectiveness—again, his ability to reshape government policy, not whether he does things we like—the most important arena may well be the bureaucracy. How much will he change the government's relationship to our society and economy by means of direct and indirect administrative action? Sophisticated friends and foes alike will watch that at least as closely as they monitor congressional developments.

It's worth remembering that even with a polarizing figure like Donald Trump, some people are of two minds, or in the middle, or persuadable in either direction. A segment of the electorate seems to end up supporting incumbent presidents who appear adequate, or slightly preferable to their challengers, even if they previously voted for the other party's candidate and aren't enthused about the president. If only for that reason, it's conceivable that Trump could win the popular vote, not just the electoral vote, if he runs again. But he will lose re-election, or perhaps not even seek it, if his popularity tanks among his base in the next couple of years and doesn't strongly rebound. Although this hasn't begun to happen yet, Trump and people close to him should remain keenly aware that many in his base like him mainly for his enemies. Anger is a powerful force in politics, but also a double-edged sword. Trump more than most presidents will need to remain visibly and audibly an outsider, even while achieving certain things by conventional standards and, if possible, getting a few more Americans to like him. That won't be easy.

* Dr. David Frisk has been a Resident Fellow at the Alexander Hamilton Institute (theahi.org) since 2013. The author of If Not Us, Who? William Rusher, National Review, and the Conservative Movement, he will teach “Modern Conservative Politics” in the Government department this fall.