On Tuesday, German police arrested three men believed to be plotting massive attacks on the Frankfurt International Airport and the U.S. military base in Ramstein. Though German authorities are relieved the attacks didn’t materialize, the foiled plots confirm that Germany is a real target for jihadists.

According to German prosecutors, the three men—two Germans and a Turk—are suspected members of Islamic Jihad Union, a radical Islamic group rooted in Uzbekistan with ties to al Qaeda. Authorities said the men had met on Sunday at a rented holiday home in the Sauerland area near Frankfurt, and were preparing to build at least one massive car bomb. The men had stockpiled more than 1,500 pounds of hydrogen peroxide, the key ingredient used in the 2005 London underground bombings that killed 56 people.

“They were planning massive attacks,” federal prosecutor Monika Harms said. “As possible targets … the suspects named discotheques and pubs and airports frequented by Americans with a view to detonating explosives loaded in cars and killing or injuring many people.”

Federal police chief Joerg Ziercke said the men had been under surveillance since December and were believed to have undergone training at an Islamic militant camp in Pakistan in 2006.

The plot to bomb Frankfurt airport and the Ramstein Air Base is merely the latest in a string of attacks foiled by German intelligence. In July, train commuters in western Germany dodged a bullet when a plot concocted by Lebanese nationals to ignite multiple timed incendiary devices aboard two German trains was foiled.

German intelligence authorities have been warning for months that the threat of attacks from jihadist cells operating inside the country’s borders is growing. Though this latest plot was foiled, Stratfor noted that the incident should be taken as more than a “wake-up call by the Germans” (September 5, emphasis ours):

By no means is Germany clear of the militant threat, however. In fact, this shows how far developed the threat is. The participation of German converts to Islam also reflects a trend of homegrown jihadists, or jihadists residing in European countries, becoming more active.

Earlier this year, German Interior Minister Wolfgang Schäuble created a brouhaha during interviews with Der Spiegel magazine and zdf television when he highlighted the growing threat of Islamic attacks on German soil. The feisty politician suggested what many perceived at the time to be rather radical steps to eliminating the threat of terrorism in Germany.

Among the legal changes Germany must consider, he said, is an allowance for “taking terrorists into preventive custody, deploying the German army in domestic operations, [and] searching suspects’ computers online without their knowledge.” He also said the “targeted killing of terrorists” was another measure Germany ought to consider.

Schäuble’s striking suggestions for beefing up the fight against radical Islam didn’t sit well with many Germans a few months ago. But that could change. As Germany, and even Europe as a whole, comes to grips with the fact that it is staring into the barrel of radical Islam, expect to see a strong shift toward tougher, more extreme measures for fighting this enemy.

A few months ago, Schäuble’s suggestions might have seemed too radical. Soon they will be deemed too mild.