mail may be the single biggest threat to the nation. Two new bills, one of them inspired by operators of adult porn sites, have joined five already on the table as federal legislators gird for battle against spam, mass e-mailings of unsolicited messages.\n The latest bills to jump on the pile are H.R. 4124, the E-Mail User Protection Act of 1998, and H.R. 4176, the Digital Jamming Act of 1998. The E-Mail User Protection Act came about after residents of Salt Lake City, Utah complained to Rep. Merrill Cook, a Republican, that they and their children were continuing to receive e-mails of a pornographic nature, said a legislative aide. Under the measure, it would be illegal to send unsolicited commercial e-mail from an unregistered or fictional domain or an unregistered or fictional e-mail address. Also, spammers could not send junk e-mail to people who subscribe to an Internet service provider unless they abide by the rules of that provider regarding e-mail.\n Internet service providers could file suit against violators and collect $10,000 an incident or $100,000 if the violation was particularly outrageous. It doesn't give individuals the right to sue. Instead, it requires that action on behalf of individuals must be taken by a state attorney general.\n The bill has been referred to the House Subcommittee on Telecommunications, Trade and Consumer Protection.\nThe Digital Jamming Act would outlaw the use of forged e-mail headings and fake return addresses. It would also make it illegal to send junk e-mail to anyone who has indicated they don't want to get it. In addition, it would prevent anyone who subscribes to an e-mail service from sending e-mail in violation of the service's published policies.\n The bill, introduced by Edward Markey, a Massachusetts Democrat, was referred to the House Commerce Committee.\n Both bills, and the ones that were filed before them, would likely face court challenges if enacted. Civil libertarians and constitutional scholars say the question is open to debate as to whether government should have an interest in regulating junk e-mail and whether that interest permits it to restrict free speech.