Because repukes believe war improves the economy.
World War I began with the assassination of Archduke Ferdinand in Europe. America wanted no part of it but reluctantly joined our allies.
World War II began when Hitler invaded Poland and we declared war on Japan when they bombed Pearl Harbor.
Democrats were in control of the White House and Congress.
Vietnam was waged incompetently by Lyndon Johnson, a racist Democrat. It was ended with honor by Republican Richard Nixon but the Democrat congress cut off the legs of Vietnam, pulling all military aid from them. North Vietnam violated the Paris Peace Accord, thanks to encouragement from Democrats like Jane Fonda and Hanoi John Kerry.
Iraq invaded Kuwait and we liberated Kuwait, while Democrats such as Ted Chappaquiddick Kennedy said there would be so many American casualties it would be "another Vietnam." What a buffoon.
America invaded Afghanistan after 9/11 and Americans were almost unanimously behind President Bush. We started nothing. We answer terrorists and invasions.
Under President Trump, the world is incredibly quiet, particularly after the disasters ushered in by BozoBama, who created ISIS. Trump's nominations for two Nobel Peace Prizes must make Democrats gnash their yellow teeth with hatred and anger.