"I found the new president's nationalistic inaugural address repulsive," Thomas Oppermann, the parliamentary floor leader of the Social Democrats, told Tagesspiegel, a sister publication of Handelsblatt, in an interview on the weekend.
Germany and Europe needed to pay close attention to safeguarding their interests under the new balance of power in the United States, Mr. Oppermann added, warning not to give in to Mr. Trump's "provocations."
The center-left SPD are the junior party to Chancellor Merkel's Christian Democrats in the governing right-left coalition.
Economics minister and SPD leader, Sigmar Gabriel, warned of underestimating Mr. Trump. "What we heard today were highly nationalistic tones," Mr. Gabriel told public broadcaster ZDF on Friday, adding that all that was missing from the speech was comparing parliament to a "Quasselbude" or "talking shop," a term used by Hitler before he took power to discredit the parliamentary democracy of the Weimar Republic in the 1920s and early 1930s. "I think we have to prepare for a rough ride," Mr. Gabriel said.
Meanwhile, Michael Fuchs, deputy parliamentary leader of the center-right CDU, called for more composure and moved to give Mr. Trump 100 days in order to concretely draft his government policy. Speaking to Deutschlandfunk radio on Monday morning, Mr. Fuchs also stated he was betting on the members of Mr. Trump's cabinet who would ensure the policies of the new U.S. government would not be as one-sided and radical as many feared.
Mr. Fuchs explained he was hoping Mr. Trump and Angela Merkel could have a conversation soon. "I've heard that there are already preliminary talks," Mr. Fuchs said, adding that he sees the chance of such talks taking place relatively quickly.