Unlike countries with parliamentary systems, where governing with pluralities rather than majorities is the norm, the United States has only two major parties, meaning usually one or the other is in charge of one or both houses by reasonably comfortable majorities.
That changed after the 2020 election, with the Democrats only barely in control of Congress by about 10 votes in the House of Representatives and, by virtue of Vice President Kamala Harris’ tie-breaking vote, just an official majority in the Senate, which is divided 50-50.