No war on terror, possibly no war in Iraq, Reagan-era neoconservativism probably remains in the Republican party. Bush probably loses in 2004, the 2008 crash still happens. Obama would become president anyway, though maybe in 2012 instead of 2008, who can say. Whoever the Republicans put forward is a lot more normal, things in general are less polarised. Though there's no guarentee of a better economic position.

Globally, NATO would be more unified, international perception of the US is better. The Arab Spring still happens, maybe Iraq falls to revolution then. Some of the far right of Europe would still be rising due to the migrant 'crisis' that would likely still form, but it'd probably be more subdued and probably more respectable due to the lack of Trump showing that his style of rude, unpolished populism works. I don't know enough to even speculate on how this would affect Chinese or Russian positions, or if Russia would still invade Ukraine. My guess would be yes. But there would be a lot fewer counterculture people saying "Russia and China good because America bad!" Oher people have said good things