Comment What about the Russian Orbital Segment? (Score 1) 69
Yes, the US Congress can give instructions to NASA, but half the ISS is run by the Russian Government.
NB: I am only discussing Russian modules here, NASA and its suppliers have already demonstrated the ability to build, launch and maintain the American modules.
The Russians wanted to quit the ISS in 2024, subsequently extended to 2028 at which point Unity and Zarya will be 30 years old. Zvezda, launched 2000, has had a persistent air leak in the transfer tunnel since 2019. While repairs have been made, the leak continues and has caused increased concern due to, at times, rising, significant air loss. Zarya was designed for a minimal operational lifespan of 15 years, while Zvezda, originally built for the Mir program had a designed minimal operational lifespan of 5 years, Mir itself was still OK after 15 years, but by 2030 Zvezda will have been operating for twice that long. When talking about the proposed extension from 2024, Space Policy Online site reports "Roscosmos initially declined to agree to the extension in part because it was waiting for a review by its engineers of the status of the hardware, which TASS said today was completed in February."
Other than operational life of the segments, the other risks are orbital corrections and deorbiting. Fortunately NASA and its suppliers already have orbital boost and plans for deorbiting.
Traditionally boost and other orbital corrections were performed by Progress Rockets docked to the aft port of Zvezda but SpaceX Dragon and Cygnus Cargo Vehicle craft also have that capability, and dock at the nadir port of Harmony so this can be maintained if Zvezda ceases to be operational.
Finally, deorbiting. Had the Russians committed to the 2032 date, the plan was to use multiple Progress cargo vehicles docked to the station, without the Russians the plan is to use a (single?) SpaceX Cargo Dragon.
The above was mostly assembled from multiple Wikipedia pages