Islamic State terrorists and other bloodthirsty organizations of their ilk will be eliminated as threats to peace only if the United States and other countries go on the offensive against them. Merely reacting to their barbarities leaves most of them alive to murder another day.

President Barack Obama chose the eve of the annual commemoration of the Sept. 11, 2001 attacks on America for a televised address on U.S. strategy against terrorism. More precisely, Obama outlined what he plans to do about Islamic State terrorists in Iraq and Syria.

In essence, his plan amounts to increased U.S. air attacks on Islamic State forces, more help for indigenous groups such as Iraqi Kurds who are fighting the Islamic State, and an international coalition of countries against the organization.

Until prodded by public opinion, the president had adopted the view that the Islamic State could be “contained.” Now, he claims to have seen the light and understands it needs to be destroyed.

But the history of Obama’s policies toward terrorists – whether those who behead American journalists or those who shower Israel with rockets – has been one of half-hearted resistance, and sometimes not even that. He seems to believe the United States should seek understandings with them, even at the expense of harming or alienating some of our traditional allies.

As Americans saw when Islamic terrorists attacked our consulate in Benghazi, Libya, the president’s first inclination is not to blame the terrorists themselves for their actions.

Unless Obama is ready to make a 180-degree change in attitude and policy, Americans will continue to be threatened by Islamic terrorists. Only a military, diplomatic and economic offensive meant to destroy the Islamic State and similar organizations will make us safe.

Is Obama ready to launch such an offensive? The next few weeks will tell.

It has been said the best defense is a good offense. In dealing with Islamic terrorists, the only effective defense is a campaign to destroy them.