More Americans are predicting an economic downturn in the coming year, a shift that could affect President Donald Trump as he seeks re-election, CNBC reported.

Only 28 percent of Americans think the economy will get better in the next 12 months, according to an NBC News/Wall Street Journal poll released Sunday. Meanwhile, 33 percent expect it will get worse and 37 percent believe it will stay about the same, the survey found.

Americans felt much better about the economy's prospects at the beginning of the year. In a January poll, 35 percent of respondents said they thought the economy would get better, while only 20 percent believed it would get worse and 43 percent felt it would stay about the same.

If voters sour on the economy, it would bode poorly for a president who has frequently pointed to it as a triumph. Trump, whose likely run for a second term in 2020 could be hamstrung by a poor approval rating, sees the economy as a central part of his appeal.

Many economists and executives have started to predict an economic slowdown, and even a potential recession as early as the end of 2019. It may leave Trump as the first president running for re-election during a recession since Jimmy Carter in 1980. Carter lost that election to Ronald Reagan.

George H.W. Bush lost to Bill Clinton in 1992 as the economy was recovering from a recession.