Most Americans have no idea what goes in in American party politics. My proposal would make “parties” not a part of the structure of the system. You can’t outlaw alliances, it would be a waste of time, but you can remove them from the structure. Which would remove a lot of their power, if only by opening it up to other “parties”. That’s part of the big problem right now, the structure of the federal government is built around there being 1 party that has the majority in a given chamber and a second party that has the rest of the seats. When was the last time when somebody without an R or D after their name got legislation even on the floor much less passed? Can’t do it, they’re outside the structure. Removing that structure opens things up to independents, new alliances, dissolution of alliances, and getting away from out headcount oriented politics.
What that means is you MUST ally with other groups to get your candidate into office.
To eliminate "that problem" you need to abolish single member districts and set up the US as a single electoral district where all the Congresscritters are elected in a big ol' lump.
Then you'd get your third parties and everybody would have to campaign nationwide to get enough votes ~~~~~~~~~~~ and you'd have to be REALLY REALLY RICH to even think of running for office.
You think campaign ads are bad now, wait until you have 600 politicians running those ads in every city in the country ~ ~