Passports are a relatively modern invention. Until about a century ago, entering one country didn't generally require official proof of citizenship or nationality in another one.

The rise of nation-states, nationalism, and especially World Wars I and II made it essential for international travelers to present passports when they entered a country.

Today, governments increasingly use passports as instruments of coercion. For instance, U.S. citizens can be denied a passport simply for owing money to the IRS or in child support payments. Even U.S. citizens living abroad must pay tax on their worldwide income. If they fail to do so, the government can decline to renew their passport.

Since governments use passports to enforce coercive laws and regulations, it only makes sense for those with the means to do so to acquire a passport from another country. 

Having a second passport has numerous additional benefits.

• It can expand your travel possibilities. Even a citizen whose passport usually allows easy international access can find a visa denied due to travel restrictions, trade sanctions, or political disturbances. For instance, the United States forbids U.S. citizens from visiting Cuba without obtaining a "license" from the Treasury Department. No other passport carries such a restriction.

• It can reduce your profile to terrorists. For instance, travel in many parts of the world using a U.S. passport can make you an instant target for criminal or terrorist groups. If you travel with a passport issued by a politically neutral country, you'll present a much lower profile to anyone with an axe to grind against your country.

• It gives you greater travel privacy. A U.S. passport is now equipped with biometric identifiers and a radio-frequency identity chip. It can potentially track you everywhere you travel. If you use your U.S. passport to visit a country not favored by U.S. authorities, you may face questioning—or worse—when you re-enter the United States. But, if you use your second passport to enter that country instead, no record exists of your visit in your U.S. passport.

• It allows you to travel internationally if your primary passport is lost, stolen, or withdrawn. The first measure many governments take if you come under investigation, or become an "enemy of the state," is to confiscate your passport. A second passport renders that sanction much less effective.

• It gives you the right to reside in other countries. A passport from a member of the European Union, for instance, gives you the right to live or work in any of 27 EU countries. Another example: a passport from a member of the Caribbean Community (e.g., the Commonwealth of Dominica), gives you the right to live or work in most other CARICOM countries.

• It can aid in international tax planning. For Americans, a second passport has another benefit: it is an essential prerequisite to expatriation; i.e., giving up U.S. citizenship in order to permanently disconnect from U.S. taxing authority.

A second passport, in other words, can be your key to a new world of free movement, greater flexibility, and legal tax reduction. In most cases, if you qualify for a second passport, your spouse and minor children will also qualify. 

Now that you understand the benefits of a second passport, how can you acquire one?....