Why in the world would we decide what to do with the current population of "illegal" or "undocumented" immigrants without first having a good idea of who and what makes up that population? Yet that is what every proposal to date, including the current Senate "Gang of Eight" bill does.

While 11 million has been circulated and accepted as the number of illegal/undocumenteds currently residing in the country, this number has no credible basis. Studies that estimate our nation's homeless population, for example, are notoriously suspect and result in widely divergent conclusions. Estimates of a shadow population of illegal/undocumenteds are, by definition, exponentially more questionable. Yet clearly we would want very different treatments should the actual number be 2 million or 25 million.

Even less is known about the makeup of this population. While today's overriding political narrative would have us believe the population consists primarily of hardworking, law-abiding, family-oriented Hispanics, no legislator can responsibly describe the true makeup. How could he? They are "in the dark."

To this end, any reform bill should commence by reversing the responsibilities between legislators and those to be legislated. For a period, perhaps six months, currently residing illegal/undocumenteds should be given the opportunity to come forward and register with the federal government. In so doing, they must file a wealth of information on their backgrounds, employment history, education, age dispersion, skills, taxes paid and unpaid, religion, health status, public welfare participation, family members they wish to have follow them, method of illegal entry and so on.

In exchange for truthful registration, this group will be afforded temporary immunity from prosecution related to their illegal entry. Only after Congress has been able to assess and assimilate the information obtained from this registration will it be responsibly positioned to determine what long term treatment should be afforded this group -- from full amnesty, a guest worker program, penalty payments, a path to citizenship, some other specialized status, all the way to deportation.

Some on the left will question why an illegal/undocumented should risk coming forward without knowing the consequences in advance; isn't he better off remaining hidden until it is safe to surface? Yet such concern demonstrates just how perverted our current immigration situation has become. Such response essentially casts current illegal/undocumenteds as saying, "I broke the law once and demand that you create a package of benefits for me in response." This Q-1 proposal, to the contrary, positions the illegal/undocumented as saying, "I broke the law but am willing to cooperate with the government to help it develop a remedy. I hope the government will recognize my circumstances and the risk I am taking when formulating its package." Taking this risk will likely elicit an even more compassionate legislative response.

Others on the right will question why this form of temporary amnesty should be granted at all. The critical word here is "temporary." Senator Marco Rubio, defending the Gang of Eight bill, argues that what we have today amounts to de facto amnesty. A Q-1 registration would organize and regulate this state for those who step forward until Congress can agree upon its ultimate legislation, whatever that is to contain. Until such time, we will have capped the population, stopping the problem from growing without end in sight. The delay is minimal in light of the benefits to be obtained.

Most significantly, understanding the specifics of the population to be addressed should give greater clarity to what any subsequent bill will and will not accomplish. We will know how many "good and hardworking Hispanics" are participating and how may potential radical Muslims are at issue. We will have better information to estimate future tax revenues as well as healthcare and other costs. If Congress decides it wants to permit relatives to also enter in the future it can begin to assess now who and how many rather than leaving it vague and unlimited as currently proposed.

And since the population will be capped, there is little excuse for a revival of a large illegal/undocumented population in the future as developed subsequent to the 1986 legislation. We will be better equipped to structure any E-Verify and employer participation regulations and to supervise student visa programs. And we will have better insights as to how to implement and recognize true border security.

Finally, by taking the mystery out of the equation, many of the barriers to bipartisan agreement should disappear. Once the facts can be brought into focus, there is less need and room to obfuscate the real problem with unbridgeable political rhetoric about compassion, "rights" of non-citizens, rule of law, the need to show the world who we are and so on. Only those who secretly seek failure of any ultimate legislation can responsibly object to gathering facts before acting.

William Siegel is a trustee of the Hudson Institute