The market is irrationally exuberant about Trump's tariff retreat

Open this photo in gallery: The Yangshan Port in Shanghai, China, on Feb. 1.THE NEW YORK TIMES/The New York Times News Service Strike up the band and break out the champagne. Happy days are here again. Right? After the United States and China announced a significant reduction in tariffs against one another, the S&P 500 index shot up more than 3 per cent on Monday. This is the latest retreat in U.S. President Donald Trump's unilateral global trade war, and the latest bounce for the markets. The S&P 500 has rebounded back to higher than before "Liberation Day," April 2,…