One of the great combat generals of World War II, Manton Eddy, had a favorite saying when battle reports came in: "Things are never half as good or half as bad as they look at first." Eddy believed he should wait to have enough information to make a good decision before he made one. This advice also applies to homeland security.

Before people start assigning blame, spending money and proposing fixes, they ought to have enough facts to make a respectable guess at the right thing to do. Yet where homeland security is concerned, thinking before speaking seems to be the exception rather than the norm.

It's happening now in the wake of the story about the international travels of Andrew Speaker, the Georgia resident who's infected with a rare form of tuberculosis. His sojourn and his ability to slip past border officials have spawned thousands of newspaper articles and hours of TV coverage as well as accusations that the Departments of Homeland Security and Health and Human Services were at fault.

The only thing we don't have yet are the facts necessary to make any really useful assessments about what this story might portend and how to fix the problem.

The first thing we need to understand is what Speaker knew about his illness and what various health officials told him to do. So far, the record is contradictory and confusing. But it makes a big difference. In dealing with an infectious disease, the most important instrument of control is the voluntary behavior of individuals. Getting people to do the right thing -- what is in their own best interest and that of the community -- is paramount.

This is an important teaching moment for all Americans. They need to understand the importance of their role in public and the magnitude of their responsibility. Public health officials, meanwhile, must learn how to communicate to citizens in a manner that ensures their messages are credible and understandable.

Next, we need a complete timeline of the actions taken by all officials -- not just in the U.S., but in all the countries involved. No one has all the facts yet, and we can't properly evaluate government response without them. For example, news stories have focused on Speaker's entry into the U.S. across the Canadian border. But how did he get into Canada? If a truly communicable disease crosses the ocean, and the onset of symptoms isn't visibly apparent in a few hours, then more likely than not it will reach the United States, carried by innocents infected in Canada or Mexico who have no idea they're infected.

Finally, the problem needs to be put in perspective. The U.S. already has a communicable disease problem -- big time. And the individuals entering the U.S. legally through legitimate points of entry are the least part of it.

Tuberculosis, including strains that are increasingly drug resistant, is one of the fastest growing diseases in the world. In part, this is because of the spread of HIV/AIDS, which reduces the human immune system, leaving individuals more susceptible to TB.

According the World Health Organization, more than eight million people a year get TB, and about 98 percent live in the developing world. Most illegal migration comes from the developing world to Europe and the U.S. Many of these individuals never pass through a point of entry, which is the most likely source of a human-carried pandemic. That's where the real problem is. In fact, today when the Department of Homeland Security detains an individual for removal from the United States, virtually the first step taken is to test him for TB.

That said, as the Senate considers a bill that would immediately grant legal status, including the right to pass back and forth across the U.S. border, to about 12 million individuals living unlawfully in the United States -- with no health check required -- the advice to think before acting should hold special significance.

Knee-jerk responses to one individual case make for bad public policy. In evaluating homeland security, sizing-up public health policies, and passing immigration laws, we ought to proceed a little more thoughtfully.

James Carafano is a senior research fellow for defense and homeland security at The Heritage Foundation and coauthor of "Winning the Long War: Lessons From the Cold War for Defeating Terrorism and Preserving Freedom".