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 $.
China is the focus of trade deficit concerns because it is the U.S.'s largest trading partner and accounts for around half of the U.S. trade deficit. However, the administration may be limited in what it can do to China, according to a report by risk consultants Control Risks.