In an op-ed article last week, Michael J. Morell, a former deputy and acting director of the Central Intelligence Agency, endorsed Hillary Clinton for president — and lambasted her Republican opponent, Donald J. Trump, as a threat to national security. The article jump-started a new conversation about foreign policy in this election — one that received a further boost on Monday, when 50 Republican foreign policy leaders signed a letter condemning Mr. Trump on similar grounds.

After sifting through more than a thousand reader comments, op-ed editors identified several key themes and questions and put them to Mr. Morell. Here are his answers.

Q. You praise Hillary Clinton’s poise and preparedness at the State Department, but can you speak to any real achievements during her term as secretary of state?

All the glowing praise in the NYT and the commentators for Hillary Clinton just about nonstop … Will someone please tell us just what Mrs. Clinton has accomplished during her tenure? I only see bad judgment and decisions …. Libya, Syria, Iraq, Honduras etc., taking money from Saudi Arabia and other foreign countries.— E.S., Cleveland

A. She was key to many achievements, including building the international sanctions regime against Iran, the most effective in history and the single factor that forced Tehran to the negotiating table, making possible last year’s agreement that set back Iran’s nuclear program by well over a decade; overseeing the negotiation of a new arms control treaty with Russia that reduced nuclear stockpiles to their lowest levels in decades; and brokering a cease-fire in Gaza that averted a ground war. She played a central role in bringing China and India to the table for the first time on climate change, leading to last year’s Paris accord; in opening Burma to the world and taking the initial steps that resulted in normalized relations with Cuba; and in advancing the rights of women and girls around the globe.

But in my view, her greatest achievement was her work with the rest of the national security team that prevented any attacks by an international terrorist group on the homeland. This is a remarkable achievement, given the intentions, capabilities and plots of Al Qaeda to attack us during her tenure. Secretary Clinton was a leader in our fight against terrorism. In these policy discussions, her voice carried immense weight. She supported aggressive operations against extremists, including drone strikes, the military surge in Afghanistan and the Bin Laden raid. In her diplomatic work, she worked to ensure that our allies and partners were supporting us in this critically important mission.

I think it is ironic that many of Secretary Clinton’s critics, who are raising questions today about her achievements as secretary of state, heaped praise on her both when she was in the job and when she stepped down at the end of President Obama’s first term. In 2012, Senator Lindsey Graham, Republican of South Carolina, said she was “one of the most effective secretary of states … that I have known in my lifetime.” A year earlier, Mr. Graham called her a “national treasure.” In 2014, Mike Huckabee, a former Republican governor of Arkansas, called Secretary Clinton “a policy genius.” Even Newt Gingrich, in 2013, said that she had done a “tremendous job” as secretary of state.

Q. Some people have responded to your op-ed by highlighting your work for Beacon Global Strategies, which was co-founded by former associates of Mrs. Clinton, and charging that this compromises your endorsement. How do you respond?

While I largely agree with Mr. Morrell’s analysis and conclusions (although I do not share his enthusiasm for pursuing ISIS into Syria), I also think it’s fair to point out that his employer, Beacon Global Strategies, has strong ties to Hillary Clinton.” — Anetliner Netliner, Washington, D.C. area

A. Among the many things I do in my post-government life — teaching and writing, serving on corporate boards, speaking publicly on national security issues — is work with Beacon Global Strategies, a firm that has prioritized nonpartisanship. The firm’s advisory board — composed of appointees of both Republican and Democratic presidents, as well as career military officers — make that priority clear. It all stems from a strong and shared belief that our national security is paramount and needs to be devoid of partisan politics.

Most importantly, I made the decision to speak out entirely on my own, with no other consideration given any thought. This was a deeply personal decision made on a completely personal basis. The only people I discussed the op-ed with were my family and a few very close friends. Nobody else.

Q. What are the international risks in electing a president and his supporters who have openly disparaged Hillary Clinton, President Obama, and large swaths of the globe, from Mexico to Muslims?

To me, all the heartfelt reason will not take away that half of the country is running around shouting to throw her in jail. It started with the “tea party” insanity akimbo degrading cartoons and collages of Barack Obama and morphed into something truly disgusting.— Guy Walker, New York City

Donald J. Trump’s rhetoric undermines America’s image overseas, damaging our influence and our global leadership. On a purely pragmatic level, bluster is not a tool of diplomacy. It is not how progress is made. I worked closely with the chiefs of foreign intelligence services during my three-and-a-half-year tenure as deputy director and acting director of the C.I.A. The extent to which these engagements served the national security interests of the United States depended, more than anything else, on the personal relationships and trust I built with these individuals. Our nation’s leaders get things done overseas largely through such relationships. These relationships are in our interest and require a great deal of time and effort to keep strong. In my view, it is impossible to have a relationship, let alone one of trust, if you say the kinds of things that Mr. Trump has frequently said about our closest allies and partners. The people overseas who work with us — and whom we rely on to help keep us safe — might not do so in the face of such a person.

Q. Do you have any reservations about Mrs. Clinton’s use of a private email server to handle some of her State Department communications?

While Mr. Morell is entitled to his opinion, it is amazing that he can extol Clinton’s virtues as a leader, politician, statesman, etc., without any discussion of her exclusive of a series of private, unsecure email servers to conduct the foreign policy of our country for the entirety of her tenure as Secretary of State, a period of about four years.” — jpduffy3, New York City

What matters most is what she has said: maintaining a private server was a mistake, she regrets it, and if she could rewind the tape, would not have emailed this way. But she can’t rewind. She can only do the best she can to explain it and answer any questions people have, and learn from her mistakes.

At the end of the day, people can make their decision on whom to put in the most important job on earth based on anything they want. As a voter, a career intelligence official and, most of all, as a father, I am voting for Secretary Clinton because I trust her with what I consider to be the Crown Jewels: my children. I have the benefit of seeing firsthand how seriously she took safeguarding our secrets. I not only have no concerns about that, but I strongly believe she is the best person to lead our country and keep us safe. Part of my belief is knowing her as someone who recognizes her mistakes, admits them and learns from them. That is exactly who we want handling very complex problems — not someone who thinks they know it all and says he doesn’t need anyone’s help.

Q. Hillary Clinton’s experience aside, she has a track record as a foreign-policy hawk. Is there a risk in a Clinton presidency overextending the United States further?

The effort to highlight the foreign policy dangers of a “President Trump” is leading the Democrats (e.g., Secretary Albright) and their allies to present themselves as defending national security in strongly Cold War, interventionist terms: more aggressive military intervention in Syria, the demonizing of Mr. Putin, etc. Let’s not overreact. The Syrian conflict is a man-made tragedy, but there is no evidence whatsoever that American military intervention would have more effective than it has been in numerous places in the Middle East…

– James, Flagstaff, Ariz.

Based on my time with her in the Situation Room, she is neither a hawk nor a dove. She is not ideological. She is a realist, and she is pragmatic. She is willing to do what makes sense to protect our national security, with a full understanding of the risks involved and the importance of mitigating those risks. Because of the risks, she is properly cautious — but decisive.

Like Secretary Clinton, former Secretary of Defense Robert Gates is also a realist and a pragmatist. He was a career C.I.A. officer who served presidents of both parties and who is one of our country’s foremost national security experts. I was always struck in the Situation Room how often he and Secretary Clinton were in agreement on the best path forward on the most important challenges facing our nation.