The House returns today with a new majority, new speaker, and new rules.

Democrats are expected to put California’s Nancy Pelosi back in the speaker’s chair she relinquished eight years ago. They also are moving to create two select committees, one focused on climate issues.

Another aim of House Democrats is to pass a bill that would end the partial government shutdown affecting the EPA and Interior Department—but its fate remains murky, given the GOP-controlled Senate’s resistance to take up a bill that President Trump said he won’t sign.

States are in the midst of assessing the shutdown’s...