You need to read more about how capital gain taxes work.
In your car example there would be a capital loss, so no taxes would be owed.
If you sold it for 55000, then there would be a capital gain and you would owe tax on the 5000 profit.
Here is an article that explains it relative to your example:
https://www.dmv.org/articles/income-tax-implications-of-selling-a-used-car/
Biden could not have expanded the court. That requires an act of Congress. Even if the Democrats passed such an act in the House, it would have been dead in the Senate because they have never had the needed supermajority and none of the Republicans would have voted for it.