The governor apparently violated the Mann Act, which, ironically, given its name, makes it a federal crime to transport individuals across state lines to pay them for sex.
According to an affidavit in the federal prostitution case, Spitzer agreed to pay $4,100, including transportation fees, to transport "Kristen" from New York's Penn Station to Washington Union Station and, ultimately to Room 871 of the Mayflower.
According to a cached site of the Emperors Club VIP, available at the Smoking Gun, the escort service requires "at least 48 hours notice and a minimum 55% deposit." Each "model" -- a.k.a. hooker -- is graded by the number of diamonds she has on her page. For example, a three-diamond "model" costs $1,000 per hour, whereas a seven-diamond prostitute costs $3,100 an hour.
The watchdog group Citizens for Responsibility and Ethics in Washington (CREW), in reaction to the news, said the Mann Act "carries a penalty of up to 20 years imprisonment for knowingly persuading or inducing any individual to cross state lines for the purposes of prostitution."