It's not a loss of soveriegnty - the nation itself has DECIDED that it wants to trade freely with another country. That is an example of real soverignty. If this trade agreement was forced on the US by the UN, for example, that would be a real loss.
Most supporters of these FTA's insist that economics is not a zero-sum game, that one party's benefit is not another's loss. Do you agree or disagree?
Economics is not a zero sum game, but war is not. If a given nation has more important trade relations with the US than with China, and China is trying to set up, say, a military base in that nation (extreme example), the US will be better able to get that other nation to deny China's request. This is a national security issue.
It's decided more than that. It's decided to give authority to supranational bodies, as you acknowledged. The fact that it voluntarily cedes sovereignty doesn't alter the fact that it's ceding sovereignty.
Economics is not a zero sum game, but war is not. If a given nation has more important trade relations with the US than with China, and China is trying to set up, say, a military base in that nation (extreme example), the US will be better able to get that other nation to deny China's request. This is a national security issue.
So you are admitting that this is more than an economic agreement. This is a step (however slight at first) toward some form of political consolidation. That's the point I was making.