How would Western Europe have voted in U.S. Presidential Elections?

[KuntaKinte]

Democrat for all

Not so sure about that. In Germany at least, Bush I was extremely popular.

I guess Germany would have voted:

2008 Obama (by 85-90% or so)
2004 Kerry
2000 Gore
1996 Clinton
1992 Bush
1988 Bush
1984 Reagan
1980 Carter

The earlier elections, I have no idea. I don't think there was much coverage and public interest of US presidential elections until the 1980s.
If Kennedy would have run for reelection in 1964, he probably would have won about 95% or so.

[KuntaKinte]

How come? Was it his multilateral and inclusive approach? Was it because he supported the reunification of Germany? Or was it something else?

Yeah, it was the role he played in the process of reunification, for the most part.
And in those days, being a Republican was not a big malus for an American president in Europe.

The picture of the Republican party being a bunch of gun-loving, SUV-driving, minority-hating, anti-science Christian rednecks who are ridiculously uber-patriotic, don't care about the environment at all and enthusiastically support war against countries they couldn't even locate on an map was drawn in the 1990s.

[KuntaKinte]

Thus, even when GOP Presidents made some aggressive or unilateral moves (such as invading Grenada and Panama, bombing Libya, or building a missile defense system), Europeans generally supported them.
This is in contrast to Bush Jr.'s Presidency. Even before 9/11, Bush Jr. was extremely unpopular in Europe due to his withdrawal from anti-missile treaties and his plans for a missile defense system, despite the fact that Reagan previously supported the idea and that this idea received a lot of support in Europe before.

Of course, the German (and European) left strongly opposed this. They 1980s peace movement loathed Reagan. But the "silent majority" was still more or less loyal to the US.

And besides foreign politics, the GOP, as I pointed out, was not caricatured as negative as today. That is mostly the result of the extreme unpopularity of GWB, put in fact Republicans really have changed since Bush the elder left office. The majority of the party drifted further away from Europe, culturally and politically.