A number of scholars have asserted that the House speakership of Republican Newt Gingrich played a key role in undermining democratic norms in the United States, hastening political polarization, and increasing partisan prejudice. According to Harvard University political scientists Daniel Ziblatt and Steven Levitsky, Gingrich's speakership had a profound and lasting impact on American politics and the health of American democracy. They argue that Gingrich instilled a "combative" approach in the Republican Party, where hateful language and hyper-partisanship became commonplace, and where democratic norms were abandoned. Gingrich frequently questioned the patriotism of Democrats, called them corrupt, compared them to fascists, and accused them of wanting to destroy the United States. Gingrich was also involved in several major government shutdowns.