In April 2019, Murphy was one of thirty-four senators to sign a letter to President Trump encouraging him "to listen to members of your own Administration and reverse a decision that will damage our national security and aggravate conditions inside Central America", asserting that Trump had "consistently expressed a flawed understanding of U.S. foreign assistance" since becoming president and that he was "personally undermining efforts to promote U.S. national security and economic prosperity" through preventing the use of Fiscal Year 2018 national security funding. The senators argued that foreign assistance to Central American countries created less migration to the U.S., citing the funding's helping to improve conditions in those countries.