Theoretically you can amend the constitution at will if you control congress, the presidency, and one state legislature. You just carve up (for example) Texas to create another 150 states out of a rural area with each occupied by loyal party members. Then you admit them (only need a simple majority) and use them to push through any amendments you want. This would almost certainly trigger a civil war, but as far as I know it is legal.
TotK. Just finished all the shrines.