Ronald Reagan is the Frank Sinatra of Republican politics — all GOP politicians want to be him, and all GOP voters long for someone like him. (Just Google “second coming of Ronald Reagan.”) Enter Donald Trump, the latest Republican candidate to be compared to Reagan. Specifically, Trump supporters — in response to Trump trailing Hillary Clinton by double digits in early general election surveys — point to Reagan’s 1980 presidential bid as an example of a candidate who overcame a big deficit early in the campaign to win decisively.

Trump, should he win the Republican nomination, could beat Clinton (should she win on the Democratic side), but that fact has nothing to do with Reagan; as smart people have pointed out, 1980 is a terrible comparison to 2016.

1. Obama is getting more popular; Carter was getting less popular

The main reason Reagan came back to beat President Jimmy Carter in 1980 was that Carter was very unpopular. Carter’s image had been boosted heading into 1980 because of a rally-around-the-flag effect after the Iranian hostage crisis started. But as the crisis wore on and the economy continued to sputter, Carter’s approval rating fell from 56 percent in early January to just 39 percent by late March. My colleague Nate Silver estimated that Carter’s approval rating on Election Day had dropped to 31 percent.

This year, the opposite is happening. Obama’s approval rating, 53 percent according to Gallup, is the highest it has been in more than two years. For the first time in a long while, his approval rating exceeds his disapproval rating. A president’s approval rating doesn’t matter nearly as much when he isn’t running for re-election, but as I wrote a year ago, “for better or worse, Clinton is stuck running for Obama’s third term.” Right now, it seems to be for better. Obama’s approval rating could fall, of course, but unlike Carter’s, Obama’s approval rating bump doesn’t seem to be tied to a single event, which means it is less likely to be temporary.

2. Trump is far more unpopular than Reagan was

Trump’s favorable rating among the general electorate is, on average, 30 percent. His unfavorable rating is a sky-high 63 percent. In other words, a lot more people dislike Trump than like him. The American public was more evenly split on Reagan at a comparable point in the 1980 campaign. According to an April 1980 Cambridge Reports survey, 39 percent of Americans had a favorable view of Reagan, and 44 percent had an unfavorable view. Reagan’s net favorability rating was 28 percentage points higher than Trump’s is.

Now, Trump might get more popular after the primary campaign ends and more Republicans start carrying his banner. But Reagan was also in the heat of a primary fight until May 1980, against George H.W. Bush. It seems likely that Trump, if he wins the nomination, will be much less popular than Reagan was when he started the general election campaign.

Trump fans will, rightly, point out that even if Trump were deeply unpopular, he would still have a good shot in the general election because Clinton is also unpopular. Clinton’s average net favorability, -13 percentage points, certainly evens things out a bit, but she is a lot less disliked than Trump is. That’s far different from 1980, when Carter’s net favorability of -11 percentage points was worse than Reagan’s.

3. Clinton’s lead is expanding over Trump, while Reagan was closing on Carter

One of the great myths of the 1980 campaign is that Reagan somehow came from behind at the last moment to defeat Carter. That narrative is based primarily on Gallup polling. But the average of polls, as John Sides has pointed out, gave Reagan an edge by early summer that he never relinquished. Carter’s lead over Reagan had been dropping throughout the early part of the year, as Carter’s hostage-crisis bounce disappeared. By the end of March, a local regression estimate of all the polls had Carter’s lead under 3 percentage points. In fact, Reagan led Carter in a late March 1980 Time/Yankelovich, Skelly & White poll.

In 2016, Trump has not led in any recent polls. Clinton has led in the last 26 of them. When we apply the local regression we did to the 1980 polls to the surveys conducted this campaign, Clinton’s lead is expanding, and she is now up by a little more than 10 percentage points over Trump. This makes sense: Obama is becoming more popular, and Trump’s favorable ratings have been dropping since the beginning of the year.

This doesn’t mean that Clinton would blow out Trump by 10 points, or even that Trump can’t come back. General election polls at this point are not a reliable indicator of the outcome. But Trump would have to climb a far steeper hill than Reagan did. Indeed, Reagan barely had any hill at all. He was far more popular than Trump is, and the incumbent president, Carter, was far less popular than Obama.