Hold on it? One senator cannot stop any legislation from being passed. They can put holds on nominations requiring Senate confirmation, but not legislation. That is not the way the Senate works. An individual senator can fillibuster legislation, but if you have 60 votes, you can invoke cloture and vote on the bill.
Any senator can hold a bill, Hillary has done it, as well as most republicans. Best of all, they can do it anonymously!
Incidently, remember a few years ago Leahy begging a single republican senator to release his hold on the Leahy-Grassley FBI Reform Act?
Just took one senator to stop it cold in its tracks. A republican will do the same with the Kennedy bill.