It will protect us from the threat of stronger weapons in the future. And, in fact, it ensures that we will have the dubious distinction of having won the nuclear arms race. Some have argued that this treaty is not verifiable. It seems that argument echoes in these halls every time we debate an arms control treaty. But, again, that argument rings hollow.
Verification is a tricky thing.
All treaties, including arms control treaties, are largely based on good faith among the parties to them. Good faith in the sense that the parties who have ratified the treaty have promised to comply with the treaty's provisions. Collectively, the parties have agreed to a set of provisions, in the case of the CTBT to not perform nuclear tests. Under a multilateral treaty such as the CTBT, all parties have agreed to the provisions and are subject to a verification regime that otherwise would not exist. The CTBT says that if one party to the treaty has evidence that a test has occurred, that party can request an onsite inspection.