US Defence Secretary James Mattis will step down at the end of February, telling President Donald Trump in a letter Thursday that he has “a right to have a Secretary of Defence whose views are better aligned with yours.”
In his extraordinary letter to Trump, Mattis said that a long-held “core belief” of his “is that our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships.”

Without maintaining those alliances, he wrote, “we cannot protect our interests or serve” the role of an “indispensable nation in the free world.”
The president has frequently lashed out at America’s allies in France, the United Kingdom, Canada and Germany, while at times appearing to side with U.S. adversaries over his own officials.

source: cnbc.com