Trump has angered Mexicans, perplexed economists and energized his nationalist political base by vowing to build a wall.
Trump has angered Mexicans, perplexed economists and energized his nationalist political base by vowing to build a wall along the US frontier -- and then somehow to make Mexico pay for it.
His insistence on this point caused Mexico's President Enrique Pena Nieto to cancel a planned visit to Washington next week, and now the two countries are on a collision course.
"Mexico has taken advantage of the US for long enough," Trump said Friday, writing first on his personal Twitter account and then re-tweeting the message under his presidential handle.
"Massive trade deficits & little help on the very weak border must change, NOW!" he added.
Mexico's leaders have repeatedly said their country will never pay for the 2,000-mile (3,200-kilometer) border barrier that Trump says is needed to stop illegal immigrants and drug smugglers coming over.
Trump's response has been to ask the US Congress to find between $12 and $15 billion for construction and to help him find a way to recoup the money with some kind of tariff on Mexican imports.
His team have floated several ideas for how to do this. On Friday, for example, senior aide Kellyanne Conway told CBS This Morning that a five to 20 percent tax may be imposed at the border.
On Thursday, White House spokesman Sean Spicer had suggested that one option -- not necessarily the favored one -- would be a border adjustment tax of the kind favored by Republicans in the US Congress.
Visiting Washington on Thursday, Mexico's Foreign Minister Luis Videgaray scoffed at the notion, arguing that this would just pass the cost of the wall on to US consumers of Mexican goods.