Missile defense - as the term might suggest - is defensive, not offensive. Brilliant American scientists have developed sophisticated technologies to prevent missiles - including those armed with nuclear warheads - from reaching their intended victims. If we are willing to share this capability to protect people around the world, Sen. Jim DeMint asked, "What is controversial about that?"
I'd like to take a stab at answering the Senator's question (raised at a Heritage Foundation forum in which I was privileged to participate this week) but first, a little context is in order. Iran's ruling mullahs have the largest arsenal of ballistic missiles in the Middle East; simultaneously, they are working overtime to develop nuclear weapons. This poses an increasing threat to Israel (Tehran's explicitly stated goal is to "wipe Israel off the map"), to the U.S. (a "world without America is attainable," Iranian President Mahmoud Ahmadinejad has said), and to Europe as well -- the softest targets are often the most tempting.
Some European cities already can be reached by Iran's medium- and intermediate-range Shahab-class missiles. Many more will be within the cross-hairs once Iran acquires long-range intercontinental ballistic missiles (ICBMs)- estimates put that about six years out.
Stopping Iran's nuclear and missile development would be the best option. But the Bush administration outsourced negotiations with Iran to European diplomats who made no progress. The Obama administration has offered Iran direct negotiations. Ahmadinejad and associates initially showed no interest. More recently, they have said they'll be glad to talk - about "respect for the rights of nations" and stuff like that, but not about ending their weapons programs.
A strong bipartisan majority in Congress has prepared legislation that would impose what Secretary of State Hillary Clinton has called "crippling sanctions"- a cut-off of Iran's gasoline imports. So far, however, President Obama has been in no rush to find out whether such pressure might prove productive.