Alongside his promise of 25 million jobs, Trump has also said he can get America growing at 4% a year again. That would be almost double what Obama achieved. The U.S. hasn't seen consistent 4% economic growth since the tech boom of the late 1990s.
Of course they matter. Trade deficits arise when we import more than we export. Easy said. It's a tad bit more complicated. When we keep incurring these deficits, year after year, we use our domestic currency (the $) to pay for those imports. This results in our trade partners getting a considerable supply of those $.
If we look at the U.S. Balance of trade data, this doesn't seem to be happening. The U.S. Census Bureau keeps extensive data on U.S. trade. The trade deficit does not appear to be getting smaller, as shown by their data. Here is the size of the trade deficit for the twelve months from November 2002 to October 2003. Nov. 2002 (38,629)