My guess - around 20-25% of the US populace is sympathetic to anti-government rhetoric. That 20-25% is enough to generate a majority amongst the roughly half of the population which votes Republican. The Republican Party has a majority in one of the branches of government.
It appears that a party with a majority in one of the branches of government and that is strictly anti-government is capable of destroying the operation of a constitution that is intended to deliver government to the populace. Their bargaining power derives from the fact they are willing to destroy the government's ability to govern. After all, that is their interest.
If the US trajectory towards almost no government continues, while reneging on the US' legitimate debts to creditors, it will be interesting to witness the catastrophe. Interesting in the Chinese meaning.
Of course, the folks who will have caused the problem will continue to blame someone other than themselves.