Bruno, I think that it's just that most of Europe has got over the issues that are so polarizing in US. Like homosexuality, abortion, guns, death penalty, socialized services, even racism and sexism (we ought to remember that pakistan elected a female prime minister almost a quarter century ago, while US is yet to elect a female president).
But I don't think it's completely immune from highly divisive issues. In some countries anti-immigration and anti-islamist currents have gaining popularity and can end up becoming a serious problem. Then there's the whole european federation thing. The political and business elites have been able to keep it growing, but with the current fiscal problems in europe it doesn't seem to me too far fetched of it becoming a serious political force. The nationalism in Europe has gotten a serious blow over the last 50 years or so, but there are still millenia of history of nationalistic wars.
Back to Newt Gingrich, I personally would be very surprised if the republicans end up nominating him to run against Obama. Even if he manages to pull a stellar VP pick, I think he's going to be doomed against Obama. The usual pick of the lesser evil won't play well in Gingrich's favor with the independents and the true 'value voters'.