One of the most important questions democratic primary voters need to ask is who is capable of being the commander in chief of what used to be the most powerful and influential country in the world? The current president has shattered America’s credibility and much of our international leadership with his obeisance to the world’s dictators and abandonment of our allies and democratic principles. The next president needs to be able to pick up the pieces, recommit to our alliances, and bring the US back to its previous leadership role.

At this point, only two candidates have shown that they have the knowledge and skill to fill that role. The first is 76-year-old Joe Biden, who was at the table for all big Obama administration decisions. The second, Pete Buttigieg, at 37 years old, was a member of the intelligence community during his time in the Navy. He has proven himself vastly intelligent, unflappable in the face of incoming fire, and capable of using many different levers to create alliances and bring together disparate interests.

The other leading candidates in the democratic primary have shown no real command of, or affinity for, foreign policy. Elizabeth Warren, in fact, showed a dangerous lack of knowledge and understanding in the October debate when she said that the United States military should be out of the Middle East entirely, apparently not understanding our several military bases, treaty obligations, and power struggles among various nations and their proxies. If we were to exit entirely, the power vacuum we leave could produce devastating results, as we see with the Kurds of Northern Syria, who turned to Russia when the US abandoned them to genocide.

While Bernie Sanders is more informed that Warren, his focus has always been on domestic social change. He wants to end the country’s endless wars and states, “American power should be measured not by our ability to blow things up, but by our ability to build on our common humanity, harnessing our technology and enormous wealth to create a better life for all people.” While his multilateral outlook makes sense, he provides few details, and he is more focused on his socialist ideas and the transformation of American society and economy.

Now, then, for the two candidates who are capable of being Commander in Chief. Joe Biden claims to be able to step into the role of Commander in Chief without needing on-the-job training. Biden’s qualifications are fairly obvious. He served for eight years as Vice President of the United States. He participated in many of the security and foreign policy decisions in the Obama Administration. Before that, he spent years (decades?) as the Chairman of the Senate Committee on Foreign Relations.

He’s got two main liabilities, though. The first is his age and stamina. Whatever he says, he simply does not demonstrate the mental acuity and sharp focus he did merely four years ago. Being President is the hardest job in the world and ages people quickly. At 78, he would be the oldest President ever to take (or leave) office. Former President Jimmy Carter recently noted that he would not have been able to be President at 80 — the job is simply too demanding.

The second of Biden’s liabilities is his son, Hunter Biden. Hunter is at the center of the impeachment inquiry of President Donald Trump right now. Trump withheld aid to Ukraine in order to pressure its President to find (or manufacture) dirt on Hunter Biden, who sat on the board of directors of a Ukranian natural gas company while Biden was Vice President and in charge of Ukraine policy. It’s widely acknowledged (by the media and democrats) that Hunter Biden didn’t break any laws. However, Hunter’s activities compromise Biden, giving his family the appearance, if not reality, of shadiness. And if Hunter Biden actually, unbeknownst to us now, participated in true corruption, Joe Biden would be compromised in his ability to conduct foreign relations as an honest broker and would once again strain America’s credibility in the world.

Pete Buttigieg, the youngest Democratic candidate, has the experience, intelligence, and temperament to make the strongest Commander in Chief. Why would Buttigieg, the mayor of a small midwestern city, possess the skills, knowledge, and character to understand the threats America faces, become respected worldwide, and protect American lives and interests in the world today? First of all, he was a member of the intelligence community while serving in the US Navy in Afghanistan. While he doesn’t flaunt it, Buttigieg was the leader of his group that investigated Al-Qaida’s movements and finances around the world. He understands the stakes of sending troops into battle, because he was himself sent across the world to defend America.

Buttigieg also understands the workings of American power — both overt and soft. This includes using all sorts of political leverage to influence outcomes. He understands the levers of international power and how to project strength and protect America’s position by emphasizing our credibility and our values of freedom and democracy. He believes in acting when both our values and our interests are served. In fact, many former diplomats support him and advise his campaign.

As Admiral William H.McRaven, former Commander of the US Special Operations Command and architect of the Osama bin Laden raid, noted in the New York Times, ”We are not the most powerful nation in the world because of our aircraft carriers, our economy, or our seat at the United Nations Security Council. We are the most powerful nation in the world because we try to be the good guys. We are the most powerful nation in the world because our ideals of universal freedom and equality have been backed up by our belief that we were champions of justice, the protectors of the less fortunate.”

Buttigieg often notes the power of the United States abroad is found in our credibility. As he said to the New Yorker, “part of how we succeed — especially in the complicated, messy, asymmetric conflicts that are going to dominate the twenty-first century — is our ability to get people to trust us. And, when we lose that, we’ve got very little left.”

Buttigieg, more than anyone else in the field, has another quality that’s crucial in a stable President. He is completely unflappable. He is disciplined and doesn’t make unforced errors, always keeping the end goal in mind even as he fully commands details. Effective presidents do not melt or explode in the face of pressure. His almost preternatural calm is in direct contrast to the current president, who fires off tweets and makes decisions based on virtually no information, compromising America’s credibility, security, and democracy at almost every turn.

Another note about age. Many of today’s world leaders are of the new generation: Emmanuel Macron of France, Leo Varadkar of Ireland, Jacinda Ardern of New Zealand are but a few leaders approximately Buttigieg’s age. While he doesn’t have the lived experience of someone Biden’s age, his judgement and temperament (and some fantastic advisors) make up for wisdom accrued over the years. And as our current President makes clear daily, age does not equal wisdom.

Overall, Trump will leave the United States’ international stature greatly diminished. It will take care, determination, patience, understanding, courage, and great skill to rebuild our leadership and protect our national security.

Pete Buttigieg is up to the challenge.