In theory, TiSA (and TTIP) can be stopped by just one member state saying no, or even by the European Parliament. It has to be approved by all 28 member state governments (the European Council) and, probably, by all 28 national parliaments.
But the vote will be take-it-or-leave-it: neither the European Parliament, nor the Council, nor the national parliaments, will be able to make any changes. So in practice, expect heavy arm-twisting.
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