In recent days, the leaders of Iran's Revolutionary Guard external action force, Hezbollah, and Hamas have all pledged to retake Jerusalem from Israel.

It's not going to happen.

Amidst the growing likelihood of regional war, these threats cannot be considered idle. Working together, Israel's enemies could create havoc in its southern and northern border areas proximate to Gaza, Syria, and Lebanon. In addition, Iran has the missile capabilities to strike deep inside Israeli territory.

Fortunately, however, Israel's capabilities far exceed those of its adversaries.

For a start, it would be nearly impossible for an Iranian-led alliance to invade Israeli territory and reach Jerusalem. The Israeli Defense Forces retain a dominant position in being able to block all lines of approach to Jerusalem. At the same time, because of dramatically improved relations between Israel, Egypt, and Jordan, any attack on Jerusalem would have to come from Lebanese or Syrian territory.

That poses another problem for Israel's adversaries.

After all, when it comes to Syria, the IDF sits in a permanent overwatch position in the Golan Heights. That position would allow Israeli forces to use direct and indirect fire artillery and air power to smash any invading columns with relative impunity. Similarly, because of a forward-looking IDF posture along the Lebanese border, its forces there would quickly be able to render any invading force as militarily incapable.

Correspondingly, the only remaining realistic option for Iran and co. would be a three-pronged approach to fray Israeli territory and attempt to force the Israeli government to make concessions on Jerusalem. Such a strategy would probably involve simultaneous rocket fire from Hezbollah forces in southern Lebanon and Hamas/Islamic Jihad forces in Gaza. At the same time, Iran might use Syrian territory as a launchpad with which to deploy its ballistic missiles against Israeli cities.

To be sure, such an attack would cause Israeli casualties and force the IDF into high tempo operations.

Of course, the IDF wouldn't sit idle in a defensive posture.

Instead, with the full support of the U.S. and probably the Saudis, Israel would strike Iranian targets inside Syria and decapitate Hamas/Hezbollah command and control structures. Because Israel regards Iranian ballistic missile threats as a red-line type concern, Prime Minister Benjamin Netanyahu might also authorize retaliatory action against Iranian targets in Tehran. Hezbollah leader Hassan Nasrallah would almost certainly be targeted relentlessly.

Ultimately, as I noted last week, it was always likely that regional terrorist groups would respond to President Trump's Jerusalem announcement with fury. But now that they are doing so, there should be only one U.S. message: If you attack Israel, the U.S. will fully endorse aggressive Israeli defensive and retaliatory action.