OPINION:
Recent polling highlights President Trump’s growing strength. Good as his numbers are, his November advantage will likely be even greater. With just eight months to go, Mr. Trump is hitting his stride, while Democrats continue their stumble.
The latest Gallup poll shows Mr. Trump holding onto his “elevated” approval rating of 49 percent. That is the same as Gallup’s previous poll “and up five points from an early January poll.”
Forty-nine percent may not be a mathematical majority, but probably will be an electoral one in November. In 2016, third parties siphoned off over 5 percent of the vote. That means either major party probably will not need 51 percent to win an effective majority this November.
Put into 2016 context, 49 percent looks even stronger. It is 3 percentage points higher than the popular vote total that won Mr. Trump the White House. It is also 1 percentage point higher than Hillary Clinton’s total, which won the popular vote majority. It is currently unlikely that Democrats’ 2020 nominee will outperform 2016 Mrs. Clinton.
America’s mood on the economy argues that Mr. Trump’s polling rise may go higher still. By 7-1 (63 percent to 9 percent), Gallup found Americans saying the economy is good, versus those declaring it bad. By 2-1 (61 percent to 31 percent), they said it was getting better, versus getting worse.
The economy has been a key variable for incumbents’ re-election success. Since 1916, elected incumbents are 11-3 when seeking second terms. Of the three losers (Hoover, Carter and Bush I), each saw annual real GDP contract within a year of their election. That is unlikely for Mr. Trump now, and just as importantly: Americans feel it is unlikely.
There are also further reasons for Mr. Trump’s numbers to rise. One is that Gallup did not sample likely voters. Likely voters are more Republican than the general population. This far out, most pollsters are not focusing on the likely voter subset; however, as November draws close they will. When they do, Mr. Trump can be expected to get a further increase.
The biggest reason to expect Mr. Trump’s numbers to improve comes not from him, but his opponent — the Democrats’ eventual nominee. The partisan disenchantment that suppressed 2016 Trump and Republican numbers will afflict Democrats in 2020.
The more extreme the nominee, such as Bernie Sanders, the more moderate and conservative Democrats will abandon the ticket. A lesser version of the same will apply the more a less extreme nominee is pushed to the left to secure the nomination.
The same could also apply to Democrats from the opposite direction. If the party establishment is seen as stealing the nomination from the left — such as Mr. Sanders entering the convention with a plurality, but leaving it without the nomination — the left could leave.
Regardless of the direction, the effect would be real. And the beneficiary would be Mr. Trump and Republicans. To appreciate the effect, look back at 2016. According to exit polling four years ago, Mr. Trump lost 12 percent of Republicans and a staggering 19 percent of conservatives. Those figures cost him the popular vote majority, and nearly cost him the election. In 2020, Democrats will experience some degree of the same.
Finally, behind all Mr. Trump’s favorable numbers is a very favorable electoral vote efficiency. Despite losing the popular vote by 2 percentage points, he handily won the electoral vote. The higher his 2020 support, the more potent that efficiency becomes — securing states he narrowly won in 2016 and opening those he narrowly lost.
Mr. Trump’s good news is also Republicans’. Gallup found 32 percent of respondents identified as Republicans, but only 27 percent identified as Democrats. That is a sizable advantage in itself, but compared to 2018, it is an enormous change.
Two years ago, Democrats rode a wave into control of the House. Exit polling showed 37 percent of 2018’s voters were Democrats. That means they are now 10 percentage points off that crest, which if it holds could threaten Democrats in Trump districts.
In short, Mr. Trump looks strong now. However, he is still stronger than he looks. And he is likely to be stronger still once Democrats finish their convention carnage and choose a nominee.
• J.T. Young served in the Office of Management and Budget and at the Treasury Department.

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