By Max Boot and Michael O'Hanlon at the Armed Forces Journal - Create a U.S. Foreign Legion.

America is a land of immigrants. Their spirit of resolve, adventure, hard work and devotion to an idea bigger than themselves has made this country great. Whatever one thinks of the immigration debate today, particularly the problem of illegal immigrants, foreigners have played a central role in the building of America. Many have done so as soldiers, among them Baron von Steuben and the Marquis de Lafayette in the War of Independence.

Now is the time to consider a new chapter in the annals of American immigration. By inviting foreigners to join the U.S. armed forces in exchange for a promise of citizenship after a four-year tour of duty, we could continue to attract some of the world's most enterprising, selfless and talented individuals. We could provide a new path toward assimilation for undocumented immigrants who are already here but lack the prerequisite for enlistment: a green card. And we could solve the No. 1 problem facing the Army and Marine Corps: the fact that these services need to grow to meet current commitments yet cannot easily do so (absent a draft) given the current recruiting environment.

Not only would immigrants provide a valuable influx of highly motivated soldiers, they would also address one of America's key deficiencies in the battle against Islamist extremists: our lack of knowledge of the languages and mores in the lands where terrorists reside. Newly arrived Americans can help us avoid trampling on local sensitivities and thereby creating more enemies than we eliminate.

Skeptics might point out that in the just-concluded fiscal year, the military met most of its recruiting and retention goals. But this was done only by relaxing age and aptitude restrictions, allowing in more individuals with criminal records, and greatly increasing the number of recruiters and advertising dollars. Although we generally support what has been done to date, the logic of these measures cannot be pushed much further...