In this period of global economic gyrations, economists are debating the pros and cons of capital controls -- which means a policy of governments restricting the movement of capital across their national borders. The theory is that imposing capital controls will give an economically troubled country time to reform and stabilize.

Aside from the obvious disregard of investors' rights to decide where and how to invest, those opposed to capital controls make these fundamental economic points:

• When countries impose capital controls, they drastically reduce the incentive of foreign and domestic investors to put money into those countries -- particularly foreigners, who can't be sure they will be able to get their earnings and investments out.

• Capital controls remove the discipline of the international market, which constantly evaluates and rewards countries that pursue sound, pro-growth policies and penalizes those that do not.

• Capital controls tend to grow, because when governments ration foreign exchange they limit not only capital flows, but also people's ability to purchase imports.

• The controls isolate emerging economies and, if allowed to linger, cut off the country imposing them from worldwide economic growth.

Economist Milton Friedman has pointed out that exchange controls were "perfected" in 1934 by Hjalmar Schacht, Adolph Hitler's finance minister.