Clever of McCain was being quite clever in the reasons given for a guest worker program; the two groups - high tech and agriculture - have very different drivers; and one would argue very different criteria/solution when it comes to temporary immigration.
Whilst I'm absolutely convinced your argument is correct as it applies to migrant agricultural workers, I'm not sure a guest worker program will lead to the abuse of high earning PhD's...

When it comes to the U.S. and Mexico, the old ways won't work.

The age-old pesky U.S.-Mexico border problem has taxed the resources of both countries, led to long lists of injustices, and appears to be heading only for worse troubles in the future. Guess what? The border problem can never be solved. Why? Because the border IS the problem! It's time for a paradigm change.

Never fear, a satisfying, comprehensive solution is within reach: the Megamerge Dissolution Solution. Simply dissolve the border along with the failed Mexican government, and megamerge the two countries under U.S. law, with mass free 2-way migration eventually equalizing the development and opportunities permanently, with justice and without racism, and without threatening U.S. sovereignty or basic principles.

To read the complete solution, Google "Megamerge Dissolution Solution", or click url.

UK Visa, the situation of Ph.D.s is precisely what protected professional industries, such as medicine, don't want to fall into. For Ph.D.s there's a guest worker program, the student visa followed by the H-1B, which in practice is a very long immigration program; it takes about 6 years from when you finish grad school to get a green card, but you're not tied to a particular employer, and if you keep a job then you'll get the green card. There are some positions that only Americans can do, for instance grad students and postdocs funded by NSF grants, but their numbers are small. As a result, Americans have to compete with people from around the world. In academia people take it for granted, but elsewhere, professional workers resist that; programmers engage in racist invective against Indians, doctors enact credentialing rules that humiliate foreign doctors, and high-skill manufacturers lobby for byzantine regulations that only they will understand. Worker racism is found not only in the AFL-CIO, but in any industry.

So if no guest worker program, then what? How do we hire foreign workers then? Using the current system in place? Free up immigration quotas? The world would tilt on its axis due to the headlong rush to enter the US.

So if no guest worker program, then what? How do we hire foreign workers then? Using the current system in place? Free up immigration quotas? The world would tilt on its axis due to the headlong rush of most of the world's population to enter the US. Do you think I'm kidding? Review the annual number of non-immigrant visa applications processed worldwide - a good number of these are denied.

Yes, you increase the quotas, dramatically. Canada's experiencing a lot of brain gain by enabling more skilled workers to immigrate. Its doctors aren't as overpaid as those in the US, but that's a benefit for every Canadian who isn't a doctor.