The elimination of the last Islamic State stronghold is a win in the Global War on Terror (which has still been going on), no doubt about it. However, if we have learned one thing, it is that radical Islamic jihadists are very resilient … and hard to wipe out. We’ve been fighting the War on Terror for over 17 years. So, how do we make sure ISIS — or some mutation/offshoot/spinoff of that terrorist group — doesn’t come back?

The specter of a terrorist group bouncing back is not one to be ignored. That’s how we ended up fighting ISIS. In 2003, after the liberation of Iraq from Saddam Hussein’s regime, al-Qaida took our troops on. They lost a lot more jihadists than they killed Americans. When America was ready to vote for president in 2008, Operation Iraqi Freedom had succeeded in setting up an Iraqi government that could have emerged.

There was just one problem: Barack Obama pulled American troops out at the end of 2011. He’d called the liberation of Iraq a mistake, said it would lead to greater instability — and then he removed the one stabilizing element: an American military presence. As a result, ISIS rose up, and unleashed a wave of terror. It even managed to hit America in San Bernardino and Orlando.

So, here’s the hard truth about keeping ISIS down. We have to deploy troops. We have historical evidence of premature withdrawals causing tragedy. Not just Iraq in 2011, but Vietnam in 1974. American troops stayed in South Korea, and now that country has emerged into a functioning democracy. They even have baseball over there — and exported “The Masked Singer” to our TVs.

The defeat of ISIS has given America something very rare in the geopolitical sphere — a second chance. Can we make that second chance work? Honestly, it’s going to be difficult with the present state of the Army and Marine Corps. To be blunt, we needed a much larger force structure, and George W. Bush’s failure to push for it was a huge blunder.

Why? Because it will take about a division of troops, plus a brigade or two, to do two things that the Iraqi military needs. First, these Army units corset the Iraqi forces — in essence improving their ability to fight and win against insurgents and terrorists. Second, they serve as a deterrent against external aggression. Back them up with one or two fighter wings, and a carrier strike group in the region, and now you have the conditions for Iraq to take the long, difficult path South Korea took.

Right now, we may be lucky to deploy one or two brigades to Iraq. If that is what we can send, then we should — and President Donald Trump should negotiate a long-term status of forces agreement to ensure that those troops stay long enough to finish the job. Because as much as a permanent deployment stinks, pulling out troops only to send them back to fight round three is going to be far worse.