Sen. Joe Lieberman (I-Conn.) issued a press release concerning the Iranian assassination plot uncovered yesterday. It reads in part:

Unfortunately, it is clear that, despite heightened sanctions, Iran’s leaders in recent years have grown increasingly emboldened, to the point of recklessness. They continue to push forward aggressively towards a nuclear weapons capability, notably preparing to expand enrichment operations to the Fordow facility. They continue unabashedly to train, fund, and arm extremist terrorist groups across the region, including in Iraq, where they are directly responsible for the murder of American soldiers. They have maintained what the Treasury Department has characterized as a “secret deal” with al Qaeda, facilitating the movement of terrorists and terrorist funding across Iranian territory. They persist in waging a war of brutal repression against their own citizens. And, as we learned yesterday, the highest levels of the IRGC Qods Force — which answers directly to the Supreme Leader — are prepared to launch brazen large-scale terrorist attacks on American soil.

In short, we need to admit that nothing we have done thus far has shown any sign of changing the calculus of Iran’s leaders with regard to their most dangerous and destabilizing behaviors. This is a regime that has crossed every red line of international law and civilized conduct — and they are getting away with it. It is time for the United States and our allies to make clear to Iran’s leaders that, if they continue on their current outlaw course, they will face more than just further incremental ratcheting up of economic sanctions and diplomatic pressure.

In other words, the diplomatic “success” in passing sanctions is an operational failure. Iran’s behavior is getting worse, not better.

Jonathan Schanzer of the Foundations for Defense of Democracies has a similar take. He told me via e-mail today, “The fact that the Iranians attempted to carry out an attack on US soil during this era of heightened terrorism strikes me as utterly reckless. The risk-reward ratio in this equation makes little sense.”

He lists a number of things that the plot confirms:

1. Chairman Mike Rogers [of the House Select Committee on Intelligence] notes that this plot was approved at the highest levels of the regime. This underscores how dangerous this regime is, and how much more dangerous it will be if it gets nuclear weapons.

2. We know that the plot was executed by the Qods Force, an arm of the Islamic Revolutionary Guard Corps. This makes it impossible to deny the close relationship between the IRGC and Iran’s most powerful leaders. The IRGC is a terrorist group controlled completely by Iran’s leaders.

3. While some analysts say that Iran only sponsors regional “resistance” groups, it is clear that it is still in the terrorism game. Thus, the attacks in Argentina of the 1990s are not ancient history. They are examples of what Iran is still capable of doing if their plans are not disrupted.

Finally, I would argue that this is a defining moment for the Obama presidency. How he responds to this attempted assault on US soil will say much about his ability to handle the challenge of Iran for the rest of his presidency. Thus far, the response has been more sanctions. I sincerely hope to see more decisive action in the coming days.

So far, however, the response has been tepid: Sanctions — ho hum. Diplomatic responses — yawn. The Iranian regime can only be encouraged by such reticence. A new commander in chief can’t come soon enough.