It's hardly news that the immigration system is mess. Foreign nationals have long been slipping across the border with fake papers, and visitors who arrive in the U.S. legitimately often overstay their legal welcome without being punished. But since Sept. 11, it has become clear that terrorists have been shrewdly factoring the weaknesses of our System into their plans. In addition to their mastery of forging passports, at least three of the 19 Sept. 11 hijackers (动机者) Were here on expired visas. That's been a safe bet until now. The Immigration and Naturalization Service(INS) (移民归化局)lacks the resources, and apparently the inclination, to keep track of the estimated 2 million foreigners who have intentionally overstayed their welcome.

But this laxness(马虎)toward immigration fraud may be about to change. Congress has already taken some modest steps. The U.S.A. Patriot Act, passed in the wake of the Sept. 11 tragedy, requires the FBI, the Justice Department, the State Department and the INS to share more data, which will make it easier to stop watch listed terrorists at the border.

But what's really needed, critics say, is even tougher laws and more resources aimed at tightening up border security. Reformers are calling for a rollback of rules that hinder law enforcement. They also want the INS to hire hundreds more border patrol agents and investigators to keep illegal immigrants out and to track them down once they are here. Reformers also want to see the INS set up a database to monitor whether visa holders actually leave the country when they are required to.

All these proposed changes were part of a new border-security bill that passed the House of Representatives but died in the Senate last week. Before Sept. 11, legislation of this kind had been blocked by two powerful lobbies: universities, which rely on tuition from foreign students who could be kept out by the new law, and business, which relies on foreigners for cheap labor. Since the attacks, they've backed off. The bill would have passed this time but for congressional maneuverings and is expected to be reintroduced and to pass next year.

Also on the agenda for next year: a proposal, backed by some influential law-makers, to split the INS into two agencies a good cop that would tend to service functions like processing citizenship papers and a bad cop that would concentrate on border inspections, deportation and other functions. One reason for the division, supporters say, is that the INS has in recent years become too focused on serving tourists and immigrants. After the Sept. 11 tragedy, the INS should pay more attention to serving the millions of ordinary Americans who rely on the nation's border security to protect them from terrorist attacks.

Terrorists have obviously taken advantage of ______.

A．the legal privileges granted to foreigners

B．the excessive hospitality of the American people

C．the irresponsibility of the officials at border checkpoints

D．the low efficiency of the Immigration and Naturalization Service