By now, it's apparent that the economy prospered under Obama - and now Trump is taking all the credit for the "strong economy" in order to keep his base happy. Despite his many failures as a human being, his supporters will still vote for him because they think he is good for the economy. That, more than anything else, will be his undoing.
It's the economy, stupid" is a slight variation of the phrase "The economy, stupid", which James Carville coined as a campaign strategist of Bill Clinton's successful 1992 presidential campaign against sitting president George H. W. Bush.
Carville's original phrase was meant for the internal audience of Clinton's campaign workers as one of the three messages to focus on, the other two messages being "Change vs. more of the same" and "Don't forget health care."
Clinton's campaign advantageously used the then-prevailing recession in the United States as one of the campaign's means to successfully unseat George H. W. Bush. In March 1991, days after the ground war in Kuwait, 90% of polled Americans approved of President Bush's job performance. Later the next year, Americans' opinions had turned sharply; 64% of polled Americans disapproved of Bush's job performance in August 1992.
(Before you get too optimistic, it's worth remembering that Trump's DISAPPROVAL rating on 11/5/2016 was 58.5%, and his approval rating was only 37.5% - and he still got elected). Throughout Trump's entire term, his DISAPPROVAL rating has always been higher than his approval rating, and his approval rating has NEVER exceeded 45%.
https://www.realclearpolitics.com/epolls/other/trump_favorableunfavorable-5493.html
This morning, the Washington Post reported that, for the first time since 2007, the yields on short-term U.S. bonds eclipsed those of long-term bonds. This phenomenon has preceded every recession in the last 50 years.
In addition, Trump's trade policies have had a devastating affect on both our farmers and our allies.
A report came out last year that U.S. farm bankruptcies are on the rise due to falling agricultural product prices as well as rising interest rates:
The increase in Chapter 12 filings reflects low prices for corn, soybeans, milk and even beef. The situation for most farmers has worsened since June under retaliatory tariffs that have closed the Chinese market for soybeans and damaged exports of milk and pork.
https://www.forbes.com/sites/jessecolombo/2018/11/29/heres-why-more-american-farms-are-going-bankrupt/#6516eb465a72
The largest economy in Europe is the German economy, and it depends heavily on auto exports. The German car makers Volkswagen, Daimler and BMW all earn at least a third of their revenue in China, where auto sales have been slipping after years of explosive growth. One major factor in the slide is the barrage of trade threats that have unsettled Chinese consumers, discouraging them from buying big-ticket goods.
The Chinese, of course, are not happy either, since factory output in July fell to its slowest pace in 17 years.
https://www.nytimes.com/2019/08/14/business/german-economy.html?action=click&module=Top%20Stories&pgtype=Homepage