The Democrats could have passed a bill, but “enshrining it in the Constitution” would mean passing a Constitutional amendment. First, they would need a 2/3rds vote of Congress. That means that the Democrats couldn’t have a slim majority - they’d need a large majority. Or they’d need to find Republicans willing to vote for a Constitutional amendment protecting abortion rights. Basically an impossibility.
Even if the Democrats managed to get the Constitutional Right To Abortion passed, they would need to have 75% of the state legislatures pass it. Democrats don’t control that name state legislatures.
So perhaps the Democrats could have passed a national law, right? Except that the Republicans would inevitably filibuster this in the Senate. The Democrats could have changed the filibuster rules, but not all of them supported changing these rules. (Mainly because it would prevent them from stopping the Republicans if the Republicans regained the Senate.) Any law that was passed would inevitably have been challenged up to the conservative Supreme Court.
You could definitely criticize the Democrats for not pushing harder to pass a law guaranteeing abortion, but a Constitutional Amendment was out of reach.
Did you read what I wrote? It’s not that they decided they weren’t going to do anything. It’s that the rules of the government limit what they can do with a small majority. They can’t just unilaterally decide that they are passing a new constitutional amendment with a few vote majority in the House/Senate. They could try for a bill, but there they are limited by various other rules not to mention the conservative Supreme Court. If the Democrats had a big enough majority, they could get more bills passed.
And that being said, what’s the alternative? Allow the Republicans to get into power and hope that they don’t take away women’s rights too much? Many Republicans have already declared that they want a national abortion ban. Others have said that they want to criminalize miscarriage and ban contraception.
Voting third party (thanks to our First Past The Post system) won’t work. Sitting out the elections and not voting won’t work. The best thing to do is get as many Democrats in office as possible from local positions to the highest offices. Then, put pressure on the higher up Democrats to get a women’s rights bill passed.
At this point, and with our current political system, not supporting the Democratic candidate is essentially supporting the Republican one.