Law enforcement only works when the government of the place where the activity is is opposed to terrorism. Britain falls into that category, as does Europe, the U.S., and, (barely) Saudi Arabia or Pakistan. There have been several excellent successes against terror groups in these nations.

The cops have to be on our side, see?

In nations like Afghanistan, Iraq, Syria, and Iran, there are no effective law enforcement options. Nobody was able to go into Afghanistan with cops prior to 9/11 and arrest bin Laden. Nobody can go into Iran or Syria with a police detachment and issue a writ ordering them to stop arming Hezbollah, Hamas, and the Iraqi insurgents. Police have to stop where the borders start.

Either international economic pressure or military action have to be taken. U.N. resolutions on their own are useless.

Lebanon is a good test case. I'll believe the Lebanese government is going to disarm Hezbollah when I see it. More likely result is that Hezbollah will continue to slowly digest the Lebanese government until they're in charge completely.