Donald Trump promises to be one of the most controversial presidents in American history. He hasn’t even been sworn into office yet, and people already either love him or hate him with a passion. His election has sharply deepened the great divide already afflicting this country.

So people will judge his presidential actions according to their own prejudices and preconceptions, and that’s too bad. Like every other president, Trump deserves the benefit of the doubt until we see what he actually does with the office and objectively consider it.

We can learn most of what we need to know by paying close attention to Trump’s first 100 days in office. That time span has been used to grade the initial performances of past presidents and it can be used that way for Trump as well.

One thing we will learn is simply whether he’s keeping his campaign promises, if he introduces the plans and programs he has said he would. And we will learn how effective he is in getting his legislative priorities approved.

Of course, even if we rate him highly for sticking to his agenda and getting it enacted, that doesn’t mean we agree with his priorities. That’s another thing we will learn — whether we think on balance he will be good for the country or not.

And we should learn something about Trump that we didn’t need to learn about other presidents in their first 100 days: Just what he stands for. Even before they took the oath of office, we knew pretty much where other presidents were coming from. We knew that Ronald Reagan was a conservative and that Barack Obama was a liberal. With the exception of Dwight Eisenhower, our modern presidents have spent a lifetime honing their political beliefs and shaping them into public messages.

All we know about Donald Trump is what he has said in the last couple of years, and his statements have been all over the political map. All we can say for certain about him is that he will take a businessman’s pragmatism to the White House. He wants to win whatever deal he is in.

Give the limits of Twitter, we are not likely to discern a guiding principle or core beliefs from Trump’s 140-character outbursts. People need to stop reacting so much to what Trump says and get ready to pay attention to what he does.