It really doesn't make any difference because all of the bills will be introduced, sent to committee, changes made, submitted to House and Senate and finally the conference committee will write the guest worker bill that will pass.
And what is going to make these "guest workers" return to their home countries after their participation in the guest worker program has expired? Absolutely nothing! You might as well replace the word "guest" with the word "permanent" because that's what they'll become, permanent workers. Then after they've been here long enough, they'll be in line for the next amnesty, and then American citizenship. And then the next group of "guest workers" will arrive in the U.S. and the whole process starts all over again.