I don't know what will happen, but tether and other centralized parts of the crypto scene are vulnerable to big government authoritarian policies much more so than bitcoin. If one didn't have to worry about control freaks in government, things would be much better.
Stablecoins such as Tether are vulnerable to authoritarian action, because unlike the case with Bitcoin or Ethereum, they are not decentralized. The authorities can seize Tether assets and make that token completely worthless. And there will be big impact on the cryptocurrency market. If Tether is not safe, then none of the stablecoins are safe. Trading will come to a halt, especially in jurisdictions where fiat currency is not permitted for trading (such as China). And indications are that USDT will be the next target after XRP.
Exactly. Anything with a central entity - be it person, small group, corporation, developer, miner etc - in a position of power is vulnerable to authoritarian control. Look at ripple. There are probably some jurisdictions that they might be safer than others from over regulation, but they are few and far between. e.g. online casinos in Antigua, others in Cook Islands, Panama etc.