More bombings in London on Thursday - although mostly failed attempts - should be unnerving to residents throughout Western countries.
Whoever the terrorists are behind the bombings - the first in London on July 7 and the second on Thursday - they seek to disrupt lives by spreading fear, along with loss of life.
No deaths occurred in the less-than-successful bombing attempts on a bus and three subway cars this week, compared with the 56 fatalities, including the four bombers, two weeks ago.
Londoners are scared with good reason. But they should not be the only ones alarmed.
These two sets of bombings might have been coordinated by the same groups; however, the second, because it apparently fizzled so badly, might have been perpetrated by copycat terrorists.
The fact the bombs Thursday didn't fully detonate provides investigators evidence to examine to determine the ingredients came from and how the bombs were constructed. Two arrests were made fairly quickly.
The two London incidents pale in comparison to the almost 3,000 deaths in the Sept. 11 airplane attacks on the World Trade Center twin towers, the Pentagon and in the fourth craft that went down in a Pennsylvania field.
However, they are reminders that evil minds bent on disrupting lives need little more than a few recruits with sick minds who are willing to end their own lives to kill others.
This spreading world threat isn't an army that wears uniforms and fights its battles under military rules of engagement. Rather, it preys on innocent civilians by using disillusioned young men, and sometimes women, strapped with bombs, to move quietly into targeted locations and die among the innocent victims.
They failed in causing deaths on Thursday, but their intent was no less clear.
The U.S. government and law enforcement groups on all levels are doing all they can to make Americans safe. Britain has taken its own steps. Yet, from a practical standpoint security can't be manned at all public transportation points. Suicide bombers can operate in the open. They do so successfully in Iraq and elsewhere.
The greatest opportunity for deterrence comes before the terrorists actually implement their plans. Stopping them in their tracks is the result of intelligence shared among cooperating agencies and hard work by investigators.
The lives of residents throughout Western countries are becoming more dependent on national and local security and law enforcement personnel. They must be well-trained and operate at the highest professional levels.