The Politics of ISDS

This anti-ISDS bill, recently introduced by some Democratic members of Congress, is an odd one:

PROHIBITION ON AGREEMENTS THAT INCLUDE INVESTOR-STATE DISPUTE SETTLEMENT PROVISIONS.

(a) IN GENERAL.—The President may not, on or after the date of the enactment of this Act, enter into any free trade agreement or investment treaty with a foreign country or countries if the agreement or treaty includes a provision described in subsection (b).

(b) PROVISION DESCRIBED.—A provision described in this subsection is a provision that grants foreign investors the right to access an international tribunal to seek cash damages from or injunctive relief against the government of the United States if such investors believe actions taken by the United States are in breach of rights conferred to foreign investors in the free trade agreement or investment treaty

I doubt anyone expects this bill to be enacted as legislation, but just for fun, let's say that it was.  What would its effect be?  As far as I can tell, virtually nothing.  Because if in the future Congress and the President wanted ISDS in a new FTA or BIT, they could just include in the FTA implementing legislation (or introduce new legislation in relation to the BIT) a provision repealing the prohibition.  So, would prohibiting ISDS through the above legislation achieve much of anything?  If you really wanted to keep ISDS out of future agreements, you could just not include it there.

I suppose introducing the bill just makes a political statement, but I wonder if there are more productive ways to make that statement.