"I wonder if, in the short-term, relations with the EU might be difficult because of some of the things the European leaders have said about Trump," McAdams said. "But maybe in the longer term they would stop. After all, the Europeans understand that they have to do business with the Americans, and in some way they put themselves into a corner because the foreign policy is really dictated in Washington."
McAdams noted, however, that France will hold elections in the spring, and the National Front party that is getting stronger has been "very favorable toward Trump."
"You have other similar anti-EU, for lack of better word, nationalist movements in Germany, and other places, Hungary, of course," he added.
McAdams also said he believed that if Trump’s Democratic rival Hillary Clinton is elected president the United States, the European Union would maintain the status quo.
"You’ll have a lot of the same retreads from the state department under the Obama administration continuing into a Clinton administration – a lot of the same people like Victoria Nuland, in the pentagon — Michelle Flournoy," McAdams explained. "You’ll have a lot of these people continue. So, I think US-European relations would continue much the same as now."
Trump has been widely criticized for his controversial statements, including in relation to women, immigrants and Muslims, promising to build a fence on the southern border with Mexico if elected president.
French president Francois Hollande said in an interview with Les Echos in June that the election of Trump would be dangerous and would complicate relations between Europe and the United States.
German Foreign Minister Frank-Walter Steinmeier in April criticized Trump for his foreign policy plan that the German top diplomat said was too far from reality.
In August, the Republican candidate was criticized by Norwegian Foreign Minister Borge Brende for his statements on women and minorities, saying that they do not belong to the modern world as they create unrest across the globe.
The US presidential election is scheduled to take place on November 8.
