By just before midnight, even Sen. McConnell was joining in. And Reince Priebus, RNC Chair, was goading other GOP Senators to get with the program and get on the floor and support Paul. In other words, McConnell announced that the Senate GOP itself was joining in.
TPM's Igor Bobic has a good run-down of all the developments here.
Some of the Republican senators seemed genuinely engaged on the issue at hand. Others were pushed generic Republican talking points. (Cruz at one point went off on gay marriage.) Some were clearly joining in because it was no longer acceptable not to join in. The 2016 presidential contest was clearly also in play.
Rejoining just before midnight, what is most amazing to me, refreshing, is that at this moment -- 12:24 AM on the East Coast -- you actually have a real debate about domestic security and war powers on the floor of the Senate. Not the normal staged nonsense but an actual debate, which got underway when Dick Durbin joined the exchange.