The defining characteristic of the battle over immigration reform has been the insistence from each side that their statistics and assertions about why and how illegal residents come to the United States are stone-cold facts.
The truth is that because illegal immigrants live in the shadows, we really don't know how much weight to give to the various claims that advocates on both sides make as they seek to change the law.
That's why a crackdown on U.S. employers who hire illegal immigrants may shed some valuable light on exactly what is going on, and how government efforts to enforce the existing law will affect both immigrants and the overall economy. It could also provide some insight into the real intentions of some of the players in the immigration debate.
The Department of Homeland Security has announced that beginning in September it will crack down on workers whose Social Security numbers do not match the names in the government computers for that account.
In other words, that should mean that illegals, or anyone else for that matter, will not be able either to get a fake card, or a fake number, just to fill out employment forms. If they do, the computers will show that number is not theirs.
Employers would then have to fire the workers or face stiff fines, not the current ones that many companies see as just the cost of doing business.
Already some business groups that hire lots of workers thought to be in the United States illegally - farmers, restaurants, janitors and construction companies - are claiming this crackdown could put them out of business, and cost legal workers their jobs, too.
During the congressional debate over immigration reform this spring that failed to produce legislation, the forces who wanted to make it easier for illegal immigrants to work here legally and eventually become citizens predicted that the U.S. economy would grind to a halt if federal officials enforced the existing statutes.
Those opposed to the reform plan that President Bush, and most of the Democratic and Republican leaders agreed to, said there were plenty of Americans willing to work, especially if the absence of illegal immigrants meant that wages would increase.
Well, the federal government is calling both sides' bluff.
And although everyone has an opinion on how best to deal with illegal immigration, facts are in short supply, and anything that separates fact from fiction will, in the long run, help clarify the debate.
However, even though most everyone says they want the current law enforced, doing so will inevitably make some people - and not just the immigrants caught in the sweep - unhappy.
Certainly, those who believe that welcoming newcomers, with or without papers, is the moral thing to do for a nation composed almost entirely of immigrants will not like the laws being actually enforced.
And, if there is indeed a serious crackdown and the economy does not fall apart, then those who said the rules should be changed because the current ones are unenforceable will have to find a new rationale. Of course, if a shortage of workers does tank the economy then it will make a powerful statement about the need for reform.
And, if the strict enforcement results in a decline in the number of folks crossing the border in the dead of night, then that too will inform the debate on the issue.
Illegal immigration is a tough issue for most Americans. There is strong resentment across the country with illegal immigrants who many believe are stealing jobs from American citizens and lowering prevailing wages for all. Yet, in a nation of immigrants, there is latent sympathy for those not fortunate enough to be born in the United States, but who come here in search of a better life for themselves and their families.
The result of the crackdown may not be pretty, but hopefully it will generate as much light as heat.