Here come the one-year retrospectives of Joe Biden's presidency as the anniversary arrives this week. Here are some guidelines for assessing them, beyond the obvious advice to be wary of partisans who would praise or pan Biden regardless of what he had done.

The most important thing to remember is that while presidents are surely the single most important players in the U.S. political system, that's all they are — single players. Even the most successful and influential presidents have limits on what they can do to influence Congress, their party, the courts, the bureaucracy, interest groups, state and local governments, private businesses, foreign governments and more. Evaluations that ignore the context that presidents work in, including the constraints they face, are useless.

The most obvious example in Biden's case is that his Democratic Party has extremely narrow margins in both house of Congress. That's in contrast to each of the other modern Democratic presidents at the beginning of their presidencies, as well as a sharp contrast with Republican Presidents Richard Nixon and George H.W. Bush, whose entire presidencies were conducted without same-party majorities in each chamber.

But that's hardly all. A conservative (and partisan) Supreme Court has already proved a serious constraint, as have several state governments that seem driven to a historically unusual degree by a partisan drive to oppose whatever the president supports. To be sure, a resourceful and skilled president might be able to overcome such things, but that doesn't mean the constraints aren't real or that the particular context doesn't heavily determine a president's opportunities.

A second caution is to be sure that any evaluation is clear about the differences between the president, the presidency and the larger political system. Former President Donald Trump was an extreme case of a leader who often received credit or blame for actions taken by executive branch actors that he had little or nothing to do with. To some extent, the president bears some responsibility for everything done by the White House staff and the entire executive branch, and there's nothing wrong with considering the records of the entire Biden or Trump administration. Just be careful if someone is conflating the performance of Biden as president with the overall performance of the Biden administration.

It gets more complicated. Congress, not the president, passes legislation; it's fair to consider how a president influenced Congress, but not to assume that whatever happened must have been what the president wanted. So beware of frustrated liberals certain that Biden betrayed them because this or that portion of their agenda has stalled, and ignore claims that had Biden really wanted something, the relevant bill would have passed.

Beware, too, of conservatives who attribute the preferences of liberal Democrats in Congress to Biden, as if he could have simply forced them to drop their priorities if he willed it. Perhaps Biden could have bargained better and perhaps not; one has to make that case, rather than just asserting that presidents should be able to get what they want. No U.S. president has ever achieved very much of that, at least not over the objections of those with whom he shares power.

It's always a good idea to be alert for the "pundit's fallacy" — the certainty that a politician would be far more successful if only he or she supported the pundit's ideas.

But even more tempting is the tendency to be swayed by the one clear and objective number that appears to evaluate a presidency all by itself: the president's approval rating. Links between presidential performance and presidential popularity are often tenuous, and lots of important things that presidents do, including most day-to-day foreign policy decisions, are unlikely to show up in approval ratings at all. When Biden's approval ratings were fairly good in his first six months, analysts often assumed that his actions must be the reason. Now that his numbers are weak, everyone wants to attribute them to the choices he's made. The exact same actions are likely to be interpreted as successes when things are going well and mistakes when they're not.

Remember that the real grade most presidents deserve after one year is "incomplete." Some processes haven't played out yet, and there may be important information that has yet to become public.

Sometimes, multiple warning signs converge. So a story that attributes high inflation, or good jobs and economic growth numbers entirely to Biden would be badly overstating any president's ability to influence the economy and may also treat the current numbers as immutable ones rather than partial results for a four- or eight-year presidency. The odds are that as long as Biden's approval numbers are low, critics will write about how inflation is hurting him, while if his approval rebounds (perhaps if the latest coronavirus wave ends), prepare to read more about the strong parts of the economy and fewer about inflation even if it remains high.

The impulse to evaluate the actions of politicians is healthy. It would be nice if the analysts didn't focus so one-dimensionally on the Oval Office, but it's a fact of American political life that there's lots of demand for reports about how Biden is doing and a lot less for evaluations of Speaker of the House Nancy Pelosi or the Chair of the Senate Finance Committee (that's Ron Wyden of Oregon, by the way) or, for that matter, Sen. Joe Manchin, the West Virginia thorn in the progressive Democrats' side.

So I'm not going to complain about the coming deluge of how's-Biden-doing opinionizing. Soak it up. Just don't take most of it too seriously.

Jonathan Bernstein is a Bloomberg Opinion columnist covering politics and policy. He taught political science at the University of Texas at San Antonio and DePauw University and wrote A Plain Blog About Politics.