Mark Foley's electronic messages to congressional pages may have been vile, despicable and outrageous, as colleagues and critics have declared.
But was his conduct illegal?
If Foley had sex with a page in the District of Columbia, it wouldn't be a crime. In the capital, the age of consent is 16, as it is in many states. That, coincidentally, is the minimum age to be a page.
However, some states -- including Foley's home state of Florida -- have enacted laws that crack down on adults who have sexual encounters with minors.
Like many jurisdictions, the district has not raised its age of consent out of concern for flooding the courts with cases involving consenting teens. But not long after Foley moved to Washington, Florida made it a felony for anyone 24 or older to have sexual relations with someone younger than 18.
Whether the 52-year-old former lawmaker and erstwhile champion of the rights of abused children will face legal action is far from clear. His lawyer has emphatically denied that Foley had sex with minors, and no page or former page has charged that the congressman seduced him.
The hodgepodge of state and federal laws on sex crimes is likely to pose a challenge for the Justice Department and for state and local authorities looking into Foley's conduct.
Many experts believe it will be hard to construct a criminal case against Foley, especially if he never acted on the messages. Federal law makes it a crime to use the Internet to entice or solicit sex from minors, but charges cannot be brought unless the actions would constitute crimes in the states where they occurred.
By resigning his seat, Foley also preempted any action the House might have taken against him for violating its rules.
The House ethics code states that a congressman "shall conduct himself at all times in a manner which shall reflect creditably on the House of Representatives." In the past, the ethics committee has interpreted that clause to conclude that "any sexual advance or relationship of any kind" between a congressman and a page is "an abuse of office" and "potentially improper sexual conduct." In 1983, the House invoked that clause when it censured Rep. Gerry Studds (D-Mass.) and Rep. Dan Crane (R-Ill.) for relationships with pages.
The House also has procedures that make the offices of members liable for sexual harassment under certain circumstances. But the rules do not apply to former employees, including ex-pages.
Disparities in state laws concerning the age of consent have been a source of frustration for child advocates.
The trend has been to raise the age of the minor protected under criminal statutory rape laws, without criminalizing sexual activity between peers.
"Do you really want a 17-year-old who has had sex with his 15-year-old girlfriend to have a lifetime stigma?" asked Howard Davidson, director of the American Bar Assn. Center on Children and the Law.
But some conservatives believe that an age of consent lower than 18 sends the wrong message to teens and their partners.
"Child exploitation advocates have been fighting against this for years," said Patrick Trueman, who was chief of the Justice Department's obscenity and child abuse section in the 1980s. Trueman said laws such as the District of Columbia's age-of-consent rule are "tragic."
The state and federal laws that make it a crime to use the Internet to entice or solicit sex from minors, which might ensnare Foley, have been interpreted narrowly.
Some courts have held that words are not enough to constitute criminal conduct, according to Peter Swire, an Internet law expert at Ohio State University's law school. "One question is whether mere conversation is enough to meet the federal statute," Swire said, adding that some courts could find that speech is protected under the First Amendment.
In most enticement cases, prosecutors have brought charges only where the suspect has taken some action to consummate plans. A Tennessee man, for example, was prosecuted a few years ago for soliciting sex with a minor after he showed up for a planned rendezvous at a hotel carrying a box of condoms and a teddy bear.
E-mails and instant messages that have surfaced so far in the Foley case appear to fall far short of that standard.
ABC News has reported that Foley sent an instant message to a San Diego teen who was uncomfortable when Foley started exploring what they might do after a dinner they were planning in Washington.
"I have the feeling that you are fishing here," the teen replied. "Im [sic] not sure what I would be comfortable with ... well [sic] see."
But no evidence has emerged that the two ever met, and experts said the exchange appeared not to rise to criminality.
At the same time, many prosecutors have seized on predators' use of the Internet. Because Foley went online to communicate with pages across the country, he may be subject to laws in different jurisdictions.
Some reports indicate that Foley sent messages to pages from his Palm Beach-area home. In that event, Florida might be able to apply its tough laws even if Foley were communicating with a youth elsewhere.
Besides its age-of-consent rules, Florida also makes it a felony to use the Internet to "seduce, solicit, lure or entice" a child to have sex or to attempt to do so.
The state's courts recently upheld a case against a Virginia man who was attempting to seduce a child in Florida. The man tried to argue that the solicitation occurred in his home state. But a court held that Florida authorities could pursue him, according to Jay Howell, a Jacksonville lawyer and former director of the National Center for Missing and Exploited Children.
"They are subtle issues in each case," Howell said.