(CNN) President Donald Trump on Friday celebrated news that the economy had added 135,000 jobs in August in a tweet that also jabbed at the media for reporting on some worrying economic signs that have popped up in recent weeks.

It was an attempt by the President to tell the public that troubling economic news -- the slowed pace of hiring, uncertainty surrounding US trade with China, the contracting American manufacturing sector -- isn't really happening. But polls are showing that the American public's confidence in the economy is starting to weaken, which could affect one of Trump's main arguments for reelection and may affect consumer spending, one of the main forces behind the country's economic growth in the last quarter.

An August Quinnipiac poll showed that for the first time in Trump's tenure, a plurality of voters said the economy is getting worse. Almost 4 in 10 said the economy is getting worse, 31% said it's getting better and 30% said it's staying the same. In a June Quinnipiac poll , only 23% said the economy was getting worse, a 14 percentage point change.

Democrats, independents, white college graduates and white women saw the biggest increases in people who said the economy is getting worse, moving either from better or those who thought it wouldn't change much. The poll showed a more than 20 percentage point jump in the proportions of Democrats, white college graduates and white women who think the economy is getting worse, and a 19 percentage point jump in the proportion of independents who say it is getting worse.

No demographic group saw a rise in those who said the economy is getting better, but Republicans and voters under 35 were the least likely to have increases in people who said the economy is getting worse (up 1 and 5 percentage points, respectively).

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