At Tuesday’s State of the Union address, President Trump argued that his pledge to make America great again had largely reached fruition.

“The days of our country being used, taken advantage of and even scorned by other nations are long behind us,” Trump said. “Gone, too, are the broken promises, jobless recoveries, tired platitudes and constant excuses for the depletion of American wealth, power and prestige.

“In just three short years,” he continued, “we have shattered the mentality of American decline, and we have rejected the downsizing of America’s destiny.”

That phrasing — shattering the mentality of American decline — is potent. It’s a reference to a sense that America was stumbling downward, a sense that Trump argues has been disassembled.

Notice, however, that Trump’s phrasing points to not an end to the decline but to the perception of decline. And before his election, few Americans contributed more to that perception than Donald Trump.

He even used the term in tweets during the presidency of Barack Obama.

That sense that Obama was pushing America downward was shared by other members of Trump’s party. In a Pew Research Center poll conducted in February 2012, nine months before the presidential election, views of how Obama had affected the economy were about split overall.

Most Democrats (and Democratic-leaning independents) said Obama had made conditions better in his first term; two-thirds of Republicans (and Republican-leaning independents) said he had made them worse. Only 9 percent of Republicans said Obama had made economic conditions better.

On Friday, Pew released an updated analysis of that question, pegged to Trump’s reelection. Opinions of how Trump has affected the economy are higher than Obama’s numbers were — primarily because Republicans overwhelmingly see his policies as having improved conditions. In 2012, only 58 percent of Democrats said Obama was making things better. Now, 80 percent of Republicans say the same of Trump.

You might justifiably be wondering where the causality lies here. Are Republicans more supportive of Trump because Trump is actually doing more to aid the economy? Or does this, like so many other things, reflect a partisan split?

Another question from Pew offers some insight. The pollsters asked how respondents view the economy. In 2016, about a third of respondents said the economy was “excellent” or “good.” Now, nearly 6 in 10 say that.

Why? Again, because of a big surge in perceptions from Republicans. Democrats are slightly less likely to say that the economy is doing well than they were in 2016, but Republicans are much, much more likely to.

The subtle change from Democrats and the big change from Republicans suggest that a central factor here may be partisanship. The graph above brought to mind one of the most remarkable bits of data that emerged in the wake of the 2016 election, which was held on Nov. 8 of that year.

Gallup asked Americans before the election (from Nov. 1 to 7) and after (Nov. 9 to 13) how they viewed the economy: Was it getting better or getting worse? Before the election, Democrats were 26 points more likely to say the economy was getting better than they were to say it was getting worse. Republicans were 65 points more likely to say it was getting worse than getting better.

Then Trump unexpectedly won the presidency.

Among Democrats, the net position swung 26 points from before Election Day to after. Among Republicans? A 70-point shift. Trump wins, and voilà! The economy is suddenly on the upswing. (Trump himself seems to agree, given how often he uses Election Day and not his inauguration as the starting point of an economic turnaround.)

It is true that the economy is doing well, as Trump highlighted elsewhere in his speech. On some metrics, though, like the “jobless recovery” Trump mentioned, things aren’t much different than they were under Obama. Particularly following a revision to jobs numbers, for example, the economy added slightly fewer jobs during each year of Trump’s presidency than it had during the last year of Obama’s.

But once Trump was victorious on Nov. 8, 2016, the mentality of American economic decline had suddenly been shattered for many Republicans, Trump included. Pew’s most recent data suggests that a central shift in reversing perceptions of how America was faring was simply the extent to which you agreed with Trump politically.

In other words, the “mentality of American decline” is to some extent just another phrasing for “how Republicans view a Democratic president.”