The recent passage of legislation creating the new Department of Homeland Security represents another personal political triumph for President Bush.

More importantly, of course, this department should -- if properly organized, led and utilized -- do much to mitigate our nation's considerable vulnerability to terrorist attack.

Unfortunately, the contribution such a long-overdue initiative will be actually able to make to reducing this vulnerability will be far less than is required -- unless the executive branch and the Congress also address what might be called the "soft underbelly of homeland insecurity":  our grievously problematic immigration situation and the dysfunctional policies and practices that contribute to it.

The associated dangers are documented in a new book by the brilliant and courageous syndicated columnist, Michelle Malkin. Malkin's Invasion: How America Still Welcomes Terrorists, Criminals and Other Foreign Menaces to our Shores and her other writings are informed by her perspective as a daughter of legal immigrants -- a perspective that both values the tremendous freedoms and opportunities afforded by this country, and clearly sees the risks associated with extending them to people who are gaining entry to this country illegally, improperly and/or ill-advisedly.

Malkin is seized with several particularly pressing defects in the conduct of U.S. immigration policy and warns that, all other things being equal, the Homeland Security Department is unlikely to address them.

They include the following: 

-- the systematic failure to track foreign students -- who they are, what they are studying and when they will leave the country;

-- a similar failure with respect to tourists; 

-- the continuing admission of what she estimates are hundreds of thousands of people from countries that are known to tolerate the presence of terrorist organizations, including some formally identified by the U.S. government as terrorist-sponsoring nations;

-- the largely ignored requirement to enforce sanctions against employers who hire illegal immigrants;

-- the insane practice of holding lotteries to allocate green cards to those living illegally in the United States (the way the terrorist who shot up Los Angeles International Airport on the Fourth of July got his immigration documents);

-- the incompetent monitoring of passengers who have landed in the United States without visas or consular screening on the grounds that their itinerary has them simply transiting enroute to other destinations. This practice, according to Malkin, has enabled thousands of Middle Eastern men to simply walk out of transient lounges and disappear into our society;

-- the lack of uniformity from one law enforcement jurisdiction to another with respect to illegal aliens, giving rise in the more laissez-faire of these locales (such as New York City, Oregon and Montgomery County, Md.,) to what amount to terrorist sanctuaries;

-- an Immigration and Naturalization Service whose standard operating procedure for illegal aliens is a "catch-and-release" approach. As Malkin points out, an illegal Jamaican immigrant by the name of Una James, who is the mother of accused sniper John Malvo and a likely material witness in connection with his case, is on the lamb today because of this INS practice.

These and other problems identified in Malkin's Invasion argue for urgent and truly comprehensive immigration reform. If, as seems likely, the new Homeland Security Department is unable or unwilling to take on this task -- even though it will be impossible to succeed in its mission without doing so -- the Congress must fill the vacuum. Given the myriad jurisdictions and "turfs" that will be involved, it may be necessary to create a special or select committee to conduct the urgently needed oversight hearings and to draft the requisite reform legislation.

Michelle Malkin persuasively argues that this is no time for business-as-usual if we are serious about the business of securing our homeland.

Frank J. Gaffney Jr. held senior positions in the Reagan Defense Department. He is currently president of the Center for Security Policy.