News about U.S. plans to require passports for people returning to or entering the United States from Canada, Mexico and the Caribbean set off a firestorm of protest last month. Critics said the requirement would complicate their lives.

If you've been convicted of drunken driving or you're traveling with children, or your spouse is not a U.S. citizen, you may encounter special problems. But anyone can get ensnared in bureaucracy at the border.

Under a plan announced by the U.S. government, everyone will need a passport to enter or re-enter the United States from the Caribbean, Bermuda and Central and South America starting Dec. 31. (You already need a passport and visa to visit some of these nations.) By Dec. 31, 2006, the same rule will apply for Mexico and Canada, and by the end of 2007 to all nations.

Several of the affected countries have protested the change, saying it would hurt tourism. Even President Bush has tempered the message, saying the U.S. should look more carefully at the idea.

But even now, many experts advise carrying a passport any time you leave the United States. Heightened concern about terrorism, they say, is turning the passport into an all-purpose ID. There's also a chance that your plane or cruise ship may be diverted to a country that requires a passport or that your own plans may change.

Even without extraordinary events, you can encounter border problems. Some examples:

Driving record: It's a little-known law, but Canada may bar visitors who have been convicted of drunken driving.

The rules are complicated. If your offense took place more than 10 years ago, you're deemed "rehabilitated" and should have no problem, said an agent of the Canadian Border Services Agency in Ottawa. If it was more than five years ago, you may apply for a temporary resident's permit, which costs $250 Canadian (about $200 U.S.) and is issued on "a case-by-case basis," he said.

If the conviction is more recent, you may be barred. Visit a Canadian consulate for details.

He was asked how Canada learns about a DUI. He responded: "When someone is arriving at a port of entry, our officers will question the person. Our officers also have access to a computer system that checks for criminal records by name and date of birth."

If you don't disclose the DUI and you get caught, you may be asked to leave Canada.

Children: If a minor is with both parents, crossing a border is usually routine. But if the child is alone, with one parent or with a third party, a letter of consent from the absent parent or guardian may be required.

The rules vary. Canada, for instance, requires notarized letters for children traveling solo or with third parties but not for those with one parent - although it's best to err on the safe side, officials said. Brazil requires that such letters be translated into Portuguese.

Noncitizen spouse: You're traveling together, legally joined as one in the United States. But to foreign governments, you're two different cases.

A couple from California, encountered this issue in February while planning a summer volunteer vacation to help a medical clinic in Belize. The man needs only a passport. But because the woman is a permanent U.S. resident who carries a Philippine passport, she'll have to apply for a visa ($60) and provide Belize with her itinerary, a bank statement and more.

But such rules are not unusual, said a passport and visa specialist with Passport Express, a Providence, R.I.,- based service that helps about 10,000 customers a year obtain passports and visa applications.

"Frequently, countries require a bank statement from visa applicants," he said, "because they want to know you have the financial means to leave the country."

Shifting politics: Under a diplomatic principle called "reciprocity," nations may play tit for tat on visa rules.

Brazil, for instance, last year began fingerprinting and photographing American travelers, matching a new U.S. policy. Its visa fee for Americans is $100.

"Brazil is very hard to work with on occasion," he said.

A Princess cruise down the Amazon last month was delayed several hours, at least partly because of immigration holdups, pushing shore excursions to the next day. A Princess Cruises spokeswoman said strong river currents were also a factor.

At the Sao Paulo airport in Brazil, A passenger from Pasadena, Calif., was asked to present a second ID, in addition to his U.S. passport, when he approached a ticket counter. His traveling companion, who went to a different ticket counter, was not asked for another ID.

To reduce your chances of encountering problems, check with the consulate or embassy of the country you plan to visit. On the Internet, www.embassy.org posts a contacts list. The U.S. State Department site, www.travel.state.gov, lists country-by-country entry rules, but they are not always updated.
All of these are listed on our web page http://www.vacationshop.com/interests/international.htm.

Make sure your visa, if required, is current; for tourists, they typically are valid for 30 or 90 days. Many nations won't accept a passport that expires in less than six months.

If you arrive and run afoul of a rule, he said, "be agreeable. Kill them with kindness."

Courtesy translates well in any country.