Julian Zelizer is a history and public affairs professor at Princeton University and the editor of "The Presidency of Barack Obama: A First Historical Assessment," a new book that Princeton University Press will publish this March. He's also the co-host of the "Politics & Polls" podcast. The opinions expressed in this commentary are his own.

(CNN) It has been a crazy year in Washington. A new president came to town making big promises about how he would upend everything that was wrong with politics and assured his supporters that nothing could get in his way. So how did he do?

Grading presidents is a difficult business. These kinds of marks, especially in such a polarized age, are always dependent on the eye of the beholder.

What looks like a total disaster to one person seems like a clear-cut victory to another. This is the essence of a nation divided by red and blue.

In an era when the very notion of "truth" has come under fire, it's hard to evaluate anything a president does and expect that there can be a rational debate about the conclusions. Good grades would be dismissed by some as supporting a dictatorial commander in chief while others will push aside bad grades as more "fake news."

Despite these challenges, here is an effort to evaluate some of the bigger aspects of how he has used the power of the presidency to pursue his objectives. The grades are not meant to say whether the objectives or actions were good or bad, so much as to think about whether he has been effective at matching up promises to outcome.

Exercising presidential power: A-

From the start, President Trump promised to flex the power of the presidency to get things done. He wouldn't be constrained by the obstacles that have stymied other presidents -- other power centers and longtime Washington norms -- so that he could achieve his goals.

The good news for Trump is that he came into a pretty powerful office and expanded its impact. He has dismantled a huge number of economic and climate regulations put into place since the 1970s and used his Twitter bullhorn to promote an agenda of conservative populism that has thrilled his base.

He has unleashed a frontal assault on immigration through increased arrests and raids by Immigration and Customs Enforcement (up 16%), attempting to stop funding for sanctuary cities, the refugee ban, attempting to end DACA, and his legitimating nativist rhetoric that should not be uttered anywhere near the Oval Office in 2018.

Although there is a major investigation underway of Russia's meddling in the 2016 election and into whether there was collusion with the Trump campaign, right now the Republican Congress has done very little in response to his Nixonian assertions of authority in going after the investigators and the journalists working on this issue.

Legislating: B-

Until the end of the year, this would have been an easy F. For a Republican president whose party controlled Congress and whose party disagreed on very little when it came to policy — a wave of right-wing legislation akin to the sweeping changes of President Lyndon Johnson's Great Society should have been smooth sailing.

But it wasn't. Trump's turbulent leadership style and the chaos that gripped Washington as a result of his leadership left the GOP fumbling the ball on health care and failing to move any signature bills through most of the year. But he redeemed himself to some extent by pushing the massive corporate tax cut through, giving the party's wealthy donors a Christmas gift.

It was a triumph. Whatever the long-term effect of increasing the budget deficit and contributing to greater inequality, Trump has benefited in the short term from some major employers, such as Apple, who have announced expansion plans, or others who have said they would give bonuses to workers. Of course, passing a corporate tax cut should be low-hanging fruit for a Republican government and it is notable that even moderate Democrats said no to the bill. And the disastrous performance on handling the proposed budget and DACA deal in the past few days is a reminder that when it comes to Capitol Hill, President Trump is no Lyndon Johnson.

Coalition building: C

Here President Trump is somewhere in the middle. Without question, he has done nothing to really expand the GOP. Despite his wins in some small constituencies that went for Obama in 2008, much of what Trump has done is to preserve the party status quo.

He has been successful at elevating the hard-line elements of the party whose principal base of power had been the House, without losing the support of many Republicans, despite the complaining from people like Sens. Bob Corker and Lindsey Graham (who quickly turn around to embrace him on the golf course or airplane). This is a measure of success given how reactionary so many of his pronouncements have been.

That said, his approval ratings suggest he has zero chance of expanding the Republican coalition and if the polling trends continue the party might suffer massive damage in the midterms, which would be the one thing that would cause everyone on the right to rethink their support. His success has also depended on a booming economy that leads many Republicans to remain quiet regardless of what he does.

America's standing in the world: D

Although there are many critics who would give him a whopping F, it is important to note that the President has made some big moves that have support. In Israel, for instance, his announcement about recognizing Jerusalem as the capital has met with strong approval, while it has been denounced by many other nations.

In the Philippines he has also been met with strong applause. But most of the world is appalled. They see a president whose policies have been reckless and who has withdrawn from great alliances to feed the America first crowd. While his Twitter war with North Korea didn't start a war, that may just be because the world has been lucky so far.

Moral Leadership: F

On this the President has spent a year failing the nation. Whatever party one belongs to, there should be no support for the kinds of statements that have come from this White House. The President should be a person who pushes the nation to live up to its highest ideals, not someone who drags our democracy down into the political mud. When an entire nation was discussing Trump's derogatory reference to Africa last week, it was hard to imagine that somewhere Martin Luther King Jr. wasn't shedding tears on the holiday meant to commemorate his work on civil rights.

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Trump has elevated the standing of racist and xenophobic organizations because of his words, and transformed the presidency into a reality show circus where anything is permissible and nothing is surprising anymore.

He has introduced a style of presidential rhetoric that is more fitting for the professional wrestling ring, at best, than for the White House. His ongoing war on the truth will forever scar our national dialogue and create permanent space for those who disseminate politically loaded lies and conspiracy theories. He has laid down a very real precedent for all future presidents to act their very worst and to abandon all effort to serve as models of public behavior.