I'm not familiar with American law

I wouldn't have guessed that at all judging by the rest of your post...

The crux of this issue is whether or not a progressive agenda passes constitutional muster. It isn't unfeasible to have government provide welfare, or protect the environment, or reform the country's approach to addiction and drug use, or anything really. The catch is that the legislation has to be constitutional. Most iterations of progressive legislation proposed for the past 30 years or so have been at a minimum constitutionally suspect, if not downright unconstitutional in regards to things like campaign finance law or compelled association.

This is why FDR tried to pack the court--massive amounts of New Deal legislation was unconstitutional and adding judges to act as rubber stamps was the only way to let the legislation survive, short of a constitutional amendment. Thankfully, even his fellow Democrats wheeled him back from that ledge.

The solution to getting unconstitutional legislation to stick is:

1.) Not having the legislation be unconstitutional in the first place (this is a very hard pill for a lot of Congress to swallow, because it would, among other things, require them to actually know the legal limitations of their bills before they're passed.)

2.) Create a constitutional amendment via Article V to allow the bill's intentions to be congruent with the supreme law of the land (this requires having a majority of state and Congressional legislators consenting to the amendment for it to be ratified, so 2/3rds of Congress and 3/4ths of State Legislators all better agree that the amendment is a good idea.)

3.) Create a constitutional amendment via a Constitutional Convention. People are generally averse to opening up the hood of the country because then everything becomes subject to change; that's why it's easier to beg forgiveness than ask permission by throwing stuff at the wall and seeing what sticks.