We are still a few months away from actual votes being cast, but the presidential campaign is taking shape. Much can change between now and February, when the Iowa Caucus happens. Current polling is also a bit speculative since most voters are not fully engaged. With those caveats in mind, the contest seems to be taking shape.

One of the key indicators of presidential strength is approval/disapproval ratings. President Trump’s staff would feel much better if he were floating around 50% approval or better, but he has never reached that mark when a wide range of polls are aggregated. He is hovering around 42%, which sounds low. Let’s compare that with previous presidents at this moment of their first term in office:

• Obama–43%
• W. Bush–55%
• Clinton–47%
• H.W. Bush–70%
• Reagan–43%
• Carter–33%

Obviously, Obama, W. Bush, Clinton, and Reagan went on to win re-election with varying degrees of comfort. Trump’s approval rating compares well with everyone but W. Bush. George H.W. Bush and Carter both lost their bids even though Bush was quite popular at this point in his presidency (thanks to the ongoing success of the First Gulf War). While Trump looks similar to some successful candidates from the past, one major difference persists. There is a remarkable lack of variability in Mr. Trump’s approval ratings. His numbers have not changed much since his inauguration, while other presidents saw more peaks and valleys throughout their first terms. Voters seem to have static views of approval and disapproval for Mr. Trump. His re-election will likely hinge on maximizing his own support, which partially explains why he is not interested in appealing to those who already view him negatively. There may not be many persuadable voters left. This is why, politically, we should expect more of the same from this White House.

At the same time, voters have more positive dispositions toward Mr. Trump’s performance on the economy, where he generally polls above 50%. There are voters who may disapprove of Mr. Trump, but support his approach to some key issues. (This is not the case with foreign affairs, where Trump generally polls poorly.) Unsurprisingly, this might make the economy the key indicator heading into next autumn. If growth begins to slow down or reverse, Trump may lose the benefit of the doubt from enough people to put him in electoral jeopardy.

The Democrats are still sorting out the field, but there are obvious developing tiers. Former Vice President Biden, Sen. Warren, and Sen. Sanders are polling between roughly 18 and 30 percent, with Biden in the definitive, but not invulnerable, lead. It is too simplistic to argue that Warren and Sanders collectively have enough supporters to topple Biden, so if one were to drop out the other could reel in the frontrunner. Voters will begin to calculate things like electability as the field winnows. Opposition to, or even hatred of, Donald Trump will drive many Democrats to rally around a candidate eventually, just as some Republicans swallowed their distaste for Trump in order to vote against Hillary Clinton. If Biden continues to poll relatively well in the Midwest, expect him to be the beneficiary of this mode of thinking. Still, there are likely a fair number of hardcore progressives who will drift toward a third party alternative (Welcome Back, Jill Stein!?) or will simply sit out the election rather than stoop to support Biden.

Sen. Harris and Mayor Buttigieg are firmly in the second tier–still well-behind, but in stable positions. Buttigieg, I am convinced, is a media darling who appeals to a narrow slice of voters, but has not been able to expand his appeal. Sen. Harris enjoyed a big bump after the first set of debates, but has settled back into the single digits. Her moment was bright but seemingly brief. She needs to do more.

The third tier is wide, thin, and includes everyone else. O’Rourke, Booker, Yang, Gabbard, and Klobuchar are all polling between 1 and 3 percent, and the remainder are less than 1 percent. It is hard to see how any of these candidates shift up to the second or first tier, though I am convinced that if it happens, it will be either Yang or Gabbard because they are unusual. It might be tempting to draw a line between those polling near 0 percent (say Inslee) and someone polling near 3 percent (like O’Rourke), but statistically they are identical. Given error rates, nothing really distinguishes them from one another. They are all long shots.

The big, macro indicators suggest President Trump will win next Fall. The economy has been healthy. While trade wars with China have been disruptive and relations with North Korea, Iran, and Russia are unpredictable, an erratic peace still covers most of our international relations. But Mr. Trump, the unique president, may not fit comfortably into predictive models made for standard politicians.