<P> Trudeau visited the White House for an official visit and state dinner on March 10, 2016 . Trudeau and Obama were reported to have shared warm personal relations during the visit, making humorous remarks about which country was better at hockey and which country had better beer . Obama complimented Trudeau's 2015 election campaign for its "message of hope and change" and "positive and optimistic vision". Obama and Trudeau also held "productive" discussions on climate change and relations between the two countries, and Trudeau invited Obama to speak in the Canadian parliament in Ottawa later in the year . </P> <P> Following the victory of Donald Trump in the 2016 U.S. presidential election, Trudeau congratulated him and invited him to visit Canada at the "earliest opportunity ." Prime Minister Trudeau and President Trump formally met for the first time at the White House on February 13, 2017, nearly a month after Trump was sworn into the office . Trump has ruffled relations with Canada with tariffs on softwood lumber . Diafiltered Milk has also been brought up by Trump as an area that needs to be negotiated . Trump is expected to renegotiate NAFTA with Canada . </P> <P> The Canadian military, like forces of other NATO countries, fought alongside the United States in most major conflicts since World War II, including the Korean War, the Gulf War, the Kosovo War, and most recently the war in Afghanistan . The main exceptions to this were the Canadian government's opposition to the Vietnam War and the Iraq War, which caused some brief diplomatic tensions . Despite these issues, military relations have remained close . </P> <P> American defense arrangements with Canada are more extensive than with any other country . The Permanent Joint Board of Defense, established in 1940, provides policy - level consultation on bilateral defense matters . The United States and Canada share North Atlantic Treaty Organization (NATO) mutual security commitments . In addition, American and Canadian military forces have cooperated since 1958 on continental air defense within the framework of the North American Aerospace Defense Command (NORAD). Canadian forces have provided indirect support for the American invasion of Iraq that began in 2003 . Moreover, interoperability with the American armed forces has been a guiding principle of Canadian military force structuring and doctrine since the end of the Cold War . Canadian navy frigates, for instance, integrate seamlessly into American carrier battle groups . </P>

When did canada and the us become allies