Mandatory voting would be the fastest way to "fix" America. Turnout based voting means you win by radicalizing your side to show up to vote. Most voters would fall into a bell curve of political preference and in the US that middle stays home. In Australia it forces both major parties back into the center so they don't scare off the majority of voters, and the extreme wings of either side typically hold little sway.

I only support mandatory voting if there is a none of the above option, and that option means the office will remain unfilled.

We cannot not have a President. Ranked choice voting would be a more practical reform.

I'd prefer another round of elections, with all of the candidates on the previous ballot disallowed.

If you force to vote the many people that wouldn't vote otherwise, you will likely have results that are not representative of what the citizens want, due to skewed data. Don't expect forced voters to represent a normal vote.

Is a blank vote not an option in the US? It is here in the Netherlands.

We have no idea if the forced voters will vote blank or not.

Do you really want voters who don't know anything about a race, and don't care, casting votes? Why do you think that would be an improvement?

The party that captures most of the uninformed voters will push to make that happen. The party that doesn't will call it an affront to our republic.