Dems have a bare sliver of a majority in the Senate, and are in the minority in the House of Representatives.
In any case, most legislation requires more than a simple majority. You need a filibuster-proof majority (60 Senators). Anything less that a majority in the house and 60 Senators requires compromise with Republicans, who are famously resistant to any compromise.
That's the end game for people who truly want to see good things in the world. Majority in the House + 60 Senators + President.