It would likely be difficult for Mexico to "immediately" stop "all" illegal immigration, as Trump asks.
Later Friday, White House spokesman Hogan Gidley said he did not have an announcement "at this time" about Trump closing down the border, but added that the president "has got to do something to fix it and he's looking at all his options." While Trump made the threat more than once Friday, his administration did not appear to take any concrete steps toward closing the border.
In response to the president's tweets, Mexican Foreign Secretary Marcelo Ebrard said Mexico would not respond to threats. He called Mexico a "great neighbor" to the U.S. He added that 1.5 million Americans live in Mexico.
Trump has long hammered Mexico over trade, pledging to crack down on what he calls abuses that sap American jobs. His claims about Mexico making money off the United States appear to relate to inaccurate assertions he has repeatedly made about the U.S. trade balance with other countries.
While Trump claims the U.S. having a trade deficit with another country is the same as "losing" money, it simply means America buys more goods from the country than the trading partner purchases from the U.S. In 2017, the U.S. had a $71 billion goods trade deficit with Mexico and a $63.6 billion deficit for both goods and services, according to the U.S. Trade Representative.
In addition, while Mexico admits fewer immigrants than the U.S., it is not clear that Mexico has the strongest or America has the weakest immigration laws in the world, according to PolitiFact.
Trump sees calls to crack down on Mexico as a strong political argument and often intensifies them when looking toward an election. The president faces what will likely be a difficult campaign for re-election next year.
He also threatened to close the southern border last year ahead of the midterm elections. At the time, Trump's rhetoric sparked concerns about economic damage from closing points of entry with a vital trading partner.
States Trump aims to win next year such as Arizona and Texas rely heavily on trade with Mexico.
Neither the White House nor the Department of Homeland Security immediately responded to CNBC's requests to comment on his tweets.
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