Why did Obama change the plan?
In his announcement, the president gave two reasons for the change in policy:
First, the latest intelligence indicates that Iran is concentrating on short- and medium-range missiles rather than long-range missiles.
Second, technological advances in land- and sea-based interceptors and sensors mean they can now be more effective in defending Europe. Obama also said the new approach, using advanced versions of the SM-3 ship-based missile being developed for use by the U.S. Navy, will be more cost-effective and offer the military more flexibility.
For the next two years, the United States will deploy the sea-based Aegis weapon system, the SM-3 interceptor and sensors such as the Army Navy/Transportable Radar Surveillance system to monitor threats, the White House said. More advanced systems will come later.