WASHINGTON — President Trump is taking a blowtorch to the rules that have governed world trade for decades. The “reciprocal’’ tariffs that he announced Thursday are likely to create chaos for global businesses and conflict with America’s allies and adversaries alike. Since the 1960s, tariffs — or import taxes — have emerged from negotiations between dozens of countries. Trump wants to seize the process. “Obviously, it disrupts the way that things have been done for a very long time,’’ said Richard Mojica, a trade attorney at Miller & Chevalier. “Trump is throwing that out the window … Clearly this is ripping up trade. There are going to have to be adjustments all over the place.’’ Pointing to America’s massive and persistent trade deficits – not since 1975 has the U.S. sold the rest of the world more than it’s bought — Trump charges that the playing field is tilted against U.S. companies. …Economists don’t share Trump’s enthusiasm for tariffs.