Unless you used different language for the bet, you lost it the moment it was made.
"Never" may be falsified by "at least once", but affirmed only by "never". So I'm afraid only you could have ever been on the hook for the $1M, and may still be!
Your prof made a good bet.
Still though, bad bet. The other guy can easily keep arguing that it's still just a few more years from being repealed, until one of you dies of old age.
Unless your bet was that "it will be strengthened before it is repealed" and then his position was that "it would be repealed without ever being strengthened." Still possible for neither to happen indefinitely though, leaving the bet pending.
The wording was that the Patriot Act would not be temporary, and it will not be receded, and in fact would be strengthened.