sentences:  Although during his campaign AMLO pledged to respect the rights of Central American migrants transiting Mexico, since taking office he has generally yielded to pressure from the U.S. by hardening Mexico's southern border with Guatemala and having migrants wait in Mexico, pending their immigration claims in the U.S.
  
  On the last day of a partial government shutdown between December 2018 and January 2019, caused by disputes over funding for the new barrier, both an American and Mexican highline walker crossed the US–Mexico border in "an act of solidarity to show that people can come together even when political differences tear us apart".In June 2019, a promise of a stricter Mexican asylum program and security tightening to slow the traffic of illegal immigrants into the US averted a possible tariff war between the two countries.Trump had previously threatened a 5% import tariff on all Mexican goods.