It’s not his fault, President Trump insists. It’s that danged Russia investigation that’s keeping his approval ratings from soaring. And if you ask — or, really, even if you don’t — he’s happy to make that point.

He did so Wednesday morning.

We are indeed at the point where Trump’s repeated insistences that the investigation into Russia interference in the 2016 election was “ILLEGAL” barely notes a mention. It wasn’t, of course, nor was the specific investigation by special counsel Robert S. Mueller III. Trump uses “illegal” and “treason” the way other people use “bad” or “unpleasant.” I can’t say for certain that he has at times returned restaurant meals to the kitchen by declaring that they are illegal, but I also can’t say for certain that he hasn’t.

The simplest way to demonstrate that Trump’s assertion about hitting 65 percent approval is off the mark is to show how Americans have felt about him since before he accepted the Republican presidential nomination in 2016.

Over the course of the campaign, he never got more than 44 percent support in RealClearPolitics’s average of pre-election polling that included third-party candidates. On Election Day, he landed at 46 percent. In RealClearPolitics’s averages of approval rating polls since he took office, he’s never been above 46 percent.

(Philip Bump/The Washington Post)

The first reports that Russia hoped to see Trump win the 2016 election emerged about a month after Trump won — also about a month before he took office. His approval wavered between 40 and 45 percent over his first few months in office. The average landed in the upper 30s at about the time Mueller was appointed, remaining there for most of the rest of 2017.

Put another way, Trump’s never seen numbers that are much better than 46 percent, either in electoral or approval polling. (Trump often points to the friendly results offered by Rasmussen Reports, polling that’s been a consistent outlier in RealClearPolitics’s data.)

Trump would have you believe that this is a function of the Mueller probe (which concluded in March) and the Russia investigation more broadly, setting aside the fact that the 46-percent cap predates the probe. He’s alleging that, Russia aside, his approval ratings would soar. After all, past presidents who’ve enjoyed similarly strong economic numbers have had high approval ratings.

But let’s consider the most recent example: Bill Clinton in the late 1990s.

Over the course of 1998, Clinton was often at or above 65 percent approval, according to Gallup. That year was the exception. By the end of the year, the impeachment effort was in full swing, and his approval ratings were tamped down slightly, generally hovering around 60 percent. The suggestion is that politics had a slight dampening effect on Clinton’s approval, but not to the extent that it knocked 20 points off what he enjoyed from the strong economy.

There’s a more important lesson from Clinton, though.

We’ve repeatedly shared graphs that look like the one below, showing the distribution of approval ratings over time for the past dozen presidents. The one below is from April, when Gallup had Trump back at the upper end of the narrow range of approval ratings he’s seen. (The height of the bars below indicate the number of Gallup polls in which the president saw the indicated approval rating.)

(Philip Bump/The Washington Post)

Notice, first, that even Clinton was only rarely at 65 percent during his presidency. But more importantly, notice how narrow the range of approval ratings is that Trump and Barack Obama saw during their presidencies. The little spur of higher ratings seen by Obama came at the start of his presidency, during the “honeymoon period” that new presidents often enjoy.

What happened? Well, partisanship.

In 2015, we looked at how approval ratings for Clinton’s and Ronald Reagan’s second terms compared with Obama’s and George W. Bush’s.

Here are the first two:

(Philip Bump/The Washington Post)

And the second two:

(Philip Bump/The Washington Post)

See the difference? Opposing-party approval ratings have been much lower since Bush than they were under Clinton and Reagan.

The same pattern holds for Trump. Here, for example, are views of Trump from Quinnipiac University polling over the course of his presidency. Most Democrats strongly disapprove of Trump; very few strongly approve.

(Philip Bump/The Washington Post)

What happened to Obama at the outset of his presidency? Approval from Republicans, at first decent, collapsed. The rest of his presidency followed a consistent pattern: Democrats really liked him, Republicans really hated him, and most of the movement in his approval rating was a function of independents moving up and down.

The reverse pattern has defined Trump’s approval ratings, with the key difference that independents have been more skeptical of him than they were of Obama. Meaning that his approval ratings have been lower than Obama’s.

This is pretty obviously not a function of the Russia investigation. Democrats dislike Trump primarily because he is a Republican president. But they also dislike him, pretty obviously, because Trump goes out of his way to antagonize them. Trump’s presidency is overtly predicated on delivering wins for his Republican/conservative base, an effort that includes culture-war fights that are designed to be hostile to Democratic/liberal interests. He’ll at times pay lip service to working with Democrats but only rarely has he actually acted on it. Trump is much more likely to disparage his political opponents than reach out to them. Trump’s vision of “unity” continues to be that America should unite around him, no questions asked.

Barring some external factor such as a war, it’s unlikely that any president will see approval numbers in the mid- to upper-60s anytime soon. Partisanship is simply too deeply rooted.

But Trump’s unusual in that he hasn’t even tried to mollify the opposition. From the moment he won, Democrats were shocked, alarmed and frustrated. Trump had a hill to climb to win them over, but, over the course of the campaign, he’d pledged that he’d be the guy to set partisanship aside to get things done.

The problem was that he also campaigned on being a hard-right culture warrior who’d bring the liberal elites to heel and enact the priorities that were rampant in conservative media. That’s the campaign pledge he’s actually tried to fulfill.

And that, too, is why his approval rating is what it is.