Recognizing the group's orientation and activities, within six months, the U.S. should designate Iran's Islamic Revolutionary Guards Corps a terrorist organization.

Still, we should note that while this action is necessary, it comes with risks. Evidencing as much, on Sunday, the IRGC's commanding general stated that if the U.S. does so label his group, the IRGC "will consider the U.S. armed forces equivalent to the Islamic State, all over the world and especially in the Middle East." And on Monday, Iran's foreign ministry promised to deliver a "hard, decisive and crushing" response.

Considering the IRGC's penchant for murdering U.S. military personnel, these threats cannot be considered idle.

Nevertheless, there's no doubt that the IRGC should be designated a terrorist group. That's because, whether in Iraq, Israel, Lebanon, the Persian Gulf, Syria, Yemen, or even the United States, the IRGC's activities are defined by a calculating assault on U.S. interests. The IRGC operates as the tip of Iran's revolutionary spear: Ayatollah Ali Khamenei's means of creating an arc of subjugated feudal states across the Middle East.

Countering the IRGC will always require a targeted but aggressive American response.

That said, President Trump would do well to wait for a few months in labelling the IRGC as a terrorist group.

Why?

It's the effectiveness of diplomacy, stupid.

More specifically, as the Washington Examiner explained in our Saturday editorial, the overriding objective of present U.S. diplomacy towards Iran must be an improved nuclear deal. To be effective in getting that better deal, however, the U.S. will need European governments to be open to new economic pressure on Iran. Specifically, the European Union will have to agree that should Iran refuse to renegotiate the nuclear deal, it will restrict European businesses from continuing to do business in Iran. The EU's participation is crucial because European corporations have a major footprint in the post-deal Iranian economy.

And the economy is where the IRGC comes in. After all, the IRGC isn't just Iran's external terrorist arm, it's a major economic actor inside Iran; with great influence over the construction, energy, and telecommunications sectors.

Correspondingly, were the U.S. to immediately label the IRGC a terrorist group, it would effectively mean sanctioning European corporations now doing business with IRGC-connected Iranian entities. Don't get me wrong, if the EU refuses to support the nuclear deal's renegotiation, then U.S. sanctions on EU companies will become necessary anyway. But it would be conducive to getting the EU on board with the renegotiation effort if U.S. diplomats have more negotiating room. Using the sanctions card too quickly would be to play America's diplomatic trump card prematurely.

The IRGC should be listed as a terrorist organization, but timing is everything.