Every day a flurry of parts and products are shuttled between Texas and Mexico, part of a cross-border supply chain to make everything from cars and heavy duty machinery to flat screen televisions. The future of that partnership,

President Donald Trump's threats to impose punishing tariffs on Canada and Mexico may be part of a strategy to gain leverage ahead of new negotiations on a regional trade agreement, experts said.

The 25% import levy could go into place as soon as Feb. 1.