While Washington, D.C., is consumed by issues ranging from the important (Iraq) to the downright petty (Tuesday’s apology by Illinois Democratic Sen. Dick Durbin), there’s something huge lurking out there to really worry about: infectious diseases.

The journal Foreign Affairs highlights the threat on the cover of its summer issue, asking whether we could be in for “The Next Pandemic?” The journal refers to the avian flu strain, H5N1, which has the potential to be “far more dangerous” than the Spanish flu that killed 50 million people worldwide in 1918 and 1919, including 675,000 in the United States.

[IMGCAP(1)]So far, avian flu has killed only 54 people in Asia, along with 100 million animals, mainly chickens. But that represents more than 50 percent of the people who contracted it. Spanish flu killed only 2 percent of patients.

According to Foreign Affairs, “Since it first appeared in southern China in 1997, the virus has mutated, becoming heartier and deadlier and killing a wider range of species.

“If the relentlessly evolving virus becomes capable of human-to-human transmission, develops a power of contagion typical of human influenzas and maintains its extraordinary virulence, humanity could well face a pandemic unlike any ever witnessed.”

The implication is that the death toll could be in the hundreds of millions, even a billion, given vulnerabilities in the under-developed world. A pandemic could crush the world economy.

And then, the article adds: “Or nothing could happen.”

The combined threat of infectious disease — the avian flu is just one of several menaces — plus bioterrorism presents a quandary for U.S. politicians. Do they urgently prepare for the worst, possibly wasting vast resources, or cross their fingers and hope that nothing happens?

In a remarkable June 1 speech at Harvard University, Senate Majority Leader Bill Frist (R-Tenn.) — a physician and presidential candidate — declared infectious diseases and bioterrorism “the single greatest threat to our safety and security today” and said fighting them will be the overriding purpose of his political future.

At the same time, Frist is being criticized for not moving aggressively enough to get new BioShield legislation passed, notably by Sen. Joe Lieberman (D-Conn.), who’s been driving the issue hard for years.

Frist and Lieberman are backing rival bills that offer tax, liability and other incentives to now-reluctant biotech companies to begin producing vaccines, diagnostics and therapies and to guarantee a market if they produce them.

Lieberman contends that his bill is more comprehensive, and his aides question whether Frist is pushing various Senate committees hard enough to get legislation enacted this year.

“You have a fascinating conflation of presidential politics and serious substance at work here,” said Chuck Ludlam, who’s retiring this week as a top Lieberman aide and former biotechnology lobbyist to join the Peace Corps.

“You have three presidential candidates interested in this issue,” he noted — Frist, Sen. Hillary Rodham Clinton (D-N.Y.) and Sen. Sam Brownback (R-Kan.), a co-sponsor of the Lieberman bill. “Whoever is out in front will look pretty good if the worst happens. Anyone who’s behind the curve will look like a dolt.

“There will be 9/11-style commissions all over the place and hundreds of Richard Clarkes testifying that they warned about what was coming and higher-ups didn’t listen,” he said, referring to the former White House counter-terrorism aide who charged that the Bush administration initially ignored al Qaeda.

Frist, clearly, is not ignoring the problem. In his lecture at Harvard, he said that national leaders “will not be able to look away from what could be coming soon — a front of unchecked and virulent epidemics, the potential of which could rise above your every other concern.”

“For what the world could soon face it did not see even in the great wars of the last century,” he said. “These epidemics … could be devastating beyond imagination.”

Frist said, “I propose an unprecedented effort, a ‘Manhattan Project for the 21st century’ to defend against destruction wreaked by infectious disease and biological weapons.

“I speak of substantial increases in support for fundamental research, medical education, emergency capacity and public health infrastructure … unleashing the private sector and unprecedented collaboration between government, industry and academia.”

He also proposed “creation of secure stores of treatments and vaccines and vast networks of distribution. I speak of action, without excuses, without exceptions, with the goal of protecting every American and the capability to help protect the people of the world.”

Frist declared that, “for some years, this should be the chief work of the nation, for the good reason that failing to make it so could risk the life of the nation and other nations the world over.”

After the 2001 anthrax attack, Congress passed BioShield legislation, funded at $5.6 billion, to buy drugs to fight various diseases. Frist acknowledged that the legislation leaves the country “woefully under-prepared.”

Whether a disease is spread by nature or by terrorists, Lieberman says, “we have essentially none of the diagnostics, therapeutics and vaccines we need to treat those who might be exposed or infected.

“If we don’t have these medicines, we are likely to see quarantines and panics, which will amplify the damage and disruption.” Clearly, this issue transcends Washington’s daily political games.