I've been saying this for a while, but the one the United States has been operating on since 1787 has been rendered ineffective by built-in system exploits. And when this regime is driven from power because it will be, and not without violence the next one of its ilk to come along will use those same exploits. To be clear, there will not be enough time to undo all the damage Trump and MAGA have done to the Constitution, and strengthen the government, before the next fascist regime wins back the White House using the Trump roadmap. So we can't just hope everything post-47 will be copacetic and go back to the old rule of law to proclaim, "America's back!" No, America as we knew it is gone, and it's not going to come back. And perhaps it shouldn't, either.
Still, the old Constitution has many good ideas and can be used as source material, but there needs to be a better way forward that not only puts in the necessary firewalls to stop a Trump, but also makes for a more perfect union that protects the rights of those whom white Christian nationalists would see submissive (women), silenced (political opposition), or six feet under (minorities, the LGBTQ+ community, and everyone else who doesn't look like them).
In the wake of us defeating Trumpism, we also need to realize that not every state will jump and ratify the new Constitution. We might have proper United States of America-type nations in the northeast, upper midwest, and Pacific coast. We might see states become Canadian provinces. We might see states lose their current territorial integrity and break up it's all on the table now, thanks to MAGA. But we won't have a better nation or nations without the writing of a new Constitution.
One last thing: These new nations had better make defense a top priority, because the white Christian nationalist leaders of the red states will believe God told them to reunite the entire former United States. They will not hesitate to launch an American Crusade against the secular successor nations, a Reconquista, if you will. And in those wars, the fanatics and fascists must be put down like the rabid dogs that they are once and for all.