As Trump threatens Mexico with tariffs again, the Mexican National Guard's border activities show little impact. So why are we threatening harmful tariffs in the first place?

More than 2,500 Mexican troops, from the states of Tlaxcala, Durango, Yucatán and Mexico City, have fanned out along this historically violent border city in a show of force, NBC News reported.

Canada and Mexico on Friday sought to show U.S. President Donald Trump's administration evidence of progress in curbing the flow of fentanyl opioids into the U.S. ahead of a March 4 deadline for punishing 25% tariffs on their goods imports.