In Minnesota, Democratic legislators are threatening to stay away from the state capitol this week to prevent Republicans from trying to claim control of the House of Representatives.

In Michigan, Republican senators, who are just one seat behind the Democrats, want a special election as soon as possible to fill a seat they believe can be flipped.

And in Virginia, Democratic candidates in three special elections last week were pushing hard to retain their majorities in both legislative chambers, as Democrats try to enshrine abortion rights in the state’s constitution.

As state legislatures convene around the country this month, several knife-edge fights for partisan control have magnified the degree to which political polarization has become ingrained, not just in Congress, but in statehouses across the country.

The battle to gain the upper hand puts pressure in particular on Democratic lawmakers, who, unlike the past four years, face even higher stakes. They are already are playing defense as President-elect Donald J. Trump prepares to take office again, bolstered by the Republican takeover of Congress.

“With Trump and his MAGA allies in the states returning to office, building and defending Democratic power in the states is essential,” said Heather Williams, the president of the Democratic Legislative Campaign Committee.