Adam,

That article was interesting and more than a bit hyperbolic.

I look up the reference to testing on the Caspian Sea and it's basis is one Washington Times article written in 1999. The relevant passage is this:

Iran has test fired a sea-launched ballistic missile, according to classified U.S. intelligence reports, which could be used in a devastating stealth attack against the United States or Israel for which the United States has no known or planned defense.

The reports, which are well-known to the White House but have not been disseminated to the appropriate congressional committees, detailed the test-firing by Iran of a short-range surface-to-surface missile last spring from a barge in the Caspian Sea.

Members of the congressionally mandated Commission to Assess the Ballistic Missile Threat to the United States, chaired by former Defense Secretary Donald Rumsfeld, were briefed on the Iranian test as they were writing their final report last June, but have been prevented from mentioning it in public because the information remains classified. In the report's Executive Summary, released on July 15, 1998, the commission warned of "alternative ballistic missile launch modes" such as sea launch, but did not mention Iran by name.
The commission mentioned is the Rumsfeld Commission I mentioned earlier. All of it's predictions were wildly wrong.

Let's assume for a minute this article correctly described the intelligence report and further assume the intelligence report was accurate. Where does that put us? One possible test 12 years ago. That doesn't sound like much of a development program to me.

I could go through the whole article point-by-point, but do not have the time nor the desire. You might consider motivations here as a lot of the players mentioned were heavily involved in the Rumsfeld Commission.

Speaking only for myself, this is a group of people who share a common goal in the promotion of ballistic missile defenses. In the 1990's they used the Rumsfeld Commission to bolster political support for that goal. More recently, they rediscovered EMP and come up with implausible and self-serving scenarios that were created to "prove" that missile defense is the only way to stop the "threat." Any criticism of the threat has an "answer" so that the conclusion is always the same. From the article (emphasis added):

The only possible deterrent against Iran is the prospect of failure, Dr. Graham and other experts agreed. And the only way the United States could credibly threaten an Iranian missile strike would be to deploy effective national missile defenses.

“It’s well known that people don’t go on a diet until they’ve had a heart attack,” said Claremont Institute president Brian T. Kennedy. “And we as a nation are having a heart attack” when it comes to the threat of an EMP attack from Iran.

“As of today, we have no defense against such an attack. We need space-based missile defenses to protect against an EMP attack,” he told Newsmax.
This is, in short, a very nice piece of propaganda designed to promote a specific policy objective. It's rife with internal contradictions and exaggerations. I would suggest that you treat the claims in this article with a high degree of skepticism.