Rep. Joe “You lie!” Wilson was formally scolded by fellow House members today for his “breach of decorum” during President Obama’s health care speech last week. But while the civility issue continues to get lots of press, the “truthiness” factor gets much less attention.

There are many complicated questions surrounding the health care reform bills, but the one that the South Carolina congressman fixated on — whether illegal immigrants would benefit — appears to be one of the simpler ones. Answer: No, they wouldn’t.

PolitiFact.org and other reliable sources had already debunked the myth that illegal immigrants would receive any benefit from the proposed bills. (Further evidence comes from immigrant advocates who are unhappy with these provisions.)

But as a policy analyst once told me, the immigration debate is a fact-free zone. Many people are convinced that illegal immigrants receive government services across the board.

The National Immigration Law Center publishes a detailed guide showing which federal programs immigrants are eligible for, depending on their legal status, refugee status, nation of origin, age, date of entry and about a million other things. (Click here and scroll to “Overview: Immigrant Eligibility for Federal Programs).

It’s a complex chart, but what’s clear is that most benefits are off-limits to the undocumented. Illegal immigrants are not eligible for SSI, food stamps, welfare (TANF), full-scope Medicaid, Medicare, Social Security or public housing. The one thing all immigrants do qualify for is Emergency Medicaid, including labor and delivery.

Legal immigrants also face limits on their eligibility for services, particularly if they came in after Aug. 22, 1996, when the rules changed.

Organizations like FAIR criticize the extension of services to U.S.-citizen children of undocumented immigrants. Other groups have tried to calculate the overall costs and benefits of illegal immigration, or call attention to the uneven impact of the costs.

There is plenty of room for discussion on those issues, but when it comes to immigration, unfortunately, even the simplest facts get lost in the discussion.