Mr. Trump, before you meet with Mr. Kim, these four things need to happen

“When history comes calling you answer the door. You simply have no choice. You just never know when the bell will go off again.” That’s the situation President Trump faced Thursday when he got an invitation to meet with North Korean dictator Kim Jong Un – and he did the right thing and answered the door.

The quote above comes from my friend and mentor, the late Dr. William Martel, one of Gov. Mitt Romney’s top foreign policy strategists when Romney ran for president. Martel always had a way with words, and I can picture him telling President Trump to answer the door – but remain very, very cautious.

The bell that rang for President Trump was a stunner. Kim Jong Un has reached out, and President Trump has accepted a peace overture to have a face-to-face meeting sometime before May. Incredible.

If this historic summit happens – and that is still a big if – President Trump will have achieved a feat no one ever thought possible. This would be a chance to make history on par with President Nixon going to China and the collapse of the Soviet Union. Our grandchildren and their grandchildren would learn about this in school.

But, we must be clear, nothing is certain. We are a long way from the two leaders sitting down. My guess is that they will meet somewhere along the Demilitarized Zone dividing North from South Korea, trying to solve one of the world’s most dangerous foreign policy challenges – the removal of North Korea’s nuclear weapons.

In order to make sure this potential North Korean peace offering is sincere, President Trump must be willing to test Pyongyang’s sincerity and to make sure Kim isn’t simply trying to play him for a fool.

President Trump must use all his business negotiation skills and hurry up. He doesn’t want to get sucked into a ploy where Kim gets him to the bargaining table but is unwilling to actually bargain by setting impossible conditions for the removal of his nuclear weapons.

For example, if Kim demands U.S. troops leave the Korean peninsula or demands that America destroy its own nuclear arsenal, the negotiations will implode in absurdity.

To avoid such a scenario, here is how I would recommend the Trump administration proceed:

First, President Trump should demand the meeting can only take place in South Korea – and I would insist it be at the Demilitarized Zone.

Kim is likely eager to have the meeting in his capital of Pyongyang, to show his people he delivered the ultimate prize – an American president who is trying to sue for peace on Kim’s terms.

If President Trump goes to the North we would also run the risk of legitimizing a nation that still has 100,000-plus people in prison camps and holds U.S. citizens as its captives. We simply can’t take such a risk. If North Korea demands the talks be on Kim’s home court, President Trump needs to say there won’t be talks.

Next, President Trump must make it clear to Kim that there will be no letup in planned U.S.-South Korea joint military exercise set for the end of this month. As North Korea has trained its army all winter long, Washington and Seoul must be afforded that same right. If Pyongyang insists on these exercises being cancelled, President Trump should walk away from the potential bargaining table.

Third, North Korea must get no economic incentives for coming to the bargaining table. If Kim insists on a bribe – food aid, fuel or any letup of the maximum pressure campaign of economic sanctions – President Trump needs to make it clear that won’t happen. If North Korea puts its hand out for cash, Trump needs to pull his hand away – and walk. No exceptions.

And finally, for talks to commence, North Korea must spell out at least a preliminary roadmap to what it would offer in terms of denuclearization. This will allow President Trump to ensure we aren’t about to go through a replay of the old North Korean negotiating strategy: offer talks to stall for time and build more advanced nuclear weapons and missiles.

If North Korea will not offer even the faintest idea of how, when and where it will remove its nuclear weapons from the Korean Peninsula – and it looks like Kim is just playing for time – President Trump needs to decline Kim’s invitation.

In many respects, we are very much in unchartered waters. However, President Trump is smart to test North Korea’s intentions and see what very well could be history in the making.

My gut tells me that this is most likely another in a long line of Kim family fiascos, an effort to gain sanctions relief. But the Trump administration owes it to history to give this a shot. The bell simply may never ring again.

Harry J. Kazianis (@grecianformula) is director of defense studies at the Center for the National Interest, founded by former President Richard M. Nixon. Click here, for more on Mr. Kazianis.