We are Richard Clarke and R.P. Eddy, two national security and counterterrorism experts, here to answer your questions about terrorism and other threats to mankind.

Honestly, do you think that the current American president's policies are detrimental to our standing and security in the world?

Sometimes the only explanation for Trump's actions seems to be that he is intentionally trying to harm this country. Picking fights with our EU and NATO Allies is something that only Moscow would want us to do. Abandoning what we stand for, what differentiates us from Russia, values like human rights and democracy, only diminishes our power and thereby benefits Russia. I know it sounds overly paranoid and conspiratorial, but there is a pattern of Trump actions that are patently not in our national interest. If he walks away from the Paris accord on Climate Change, that will be another example. Few nations will benefit from climate change and sea level rise. Russia, however, just might be better off in a world where its competition is flooded and Russia's frozen wastelands are suddenly made accessible and useful.

In your opinion, what are the scariest threats that the general public are oblivious to?

Of all the future risks we examined in our research for the book, the one I can not stop thinking about is Sea Level Rise. If the minority view is correct, we could see 6-9 meters rise by 2100. To deal with that kind of relocation, resettlement, reconstruction...we would have to stop spending on almost everything else (including defense and social services.) No one is really planning for that kind of event, but it could happen in the lifetime of people alive today.

What is the strangest or most outdated vetting or psychological test question you've seen administered for would-be intelligence or security agents?

I personally think that the polygraph is ridiculous and counter-productive. It is not admissible in court. In most states it is illegal to use it as a hiring procedure. Yet CIA thinks it is some sort of magic box. We have ample evidence that real spies can evade it. And many examples of innocent people "failing" the procedure. US intelligence agencies use this specious test as a surrogate for real investigation and continuous monitoring of personnel.

What risks come with developing and stockpiling weapons (like nuclear weapons in the 40s, 50s and 60s or like zero-day exploits nowadays)? Is it worth the risk?

I am very much against NSA stockpiling Zero Day attack tools involving widely used software. If they find a vulnerability, they should tell the software developer so that the problem can be patched. If NSA can find the vulnerability, so can Russia and China. It is more important that we have secure networks on our critical infrastructure than that we are able to attack others' systems. This was the recommendation that President Obama accepted from the Review Group on Intelligence and Technology. Clearly, NSA did not comply with that policy.

In the case of the Manchester bombing it has been reported that the bomber was reported to the authorities on numerous occasions. If that's the case, where did the breakdown in the warning system happen? In your opinions, should this tragedy have been avoided? What changes would you make to ensure future tragedies are prevented?

I have some sympathy for the British police and security services. They have 20,000 people on their Watch List. When someone is reported too them, they try to check them out, but if there is no evidence that they are planning an attack, the security services can not monitor them closely. Someone can go from being radicalized to being willing to die in a terrorist attack with a matter of days. How can security services know when this state of mind has changed? Inevitably, some attackers will slip through the cracks of any system designed to detect them.

What are some simple things I can do to better protect myself against cyberthreats?

I often get asked what can the individual do to protect their own computer from hacking. The truth is there is not much that you can do. No individual is going to be able to defend against a determined hacker. Even big banks with thousands of cyber security personnel and hundreds of millions of dollars in cyber programs can be penetrated. The State Department, White House, and the secret level Pentagon networks have been victims of successful hacks. Nonetheless, you can make it difficult for the less capable hackers by 1) keeping your software and anti-virus up to date with the latest patches, 2) not using public WiFi networks, 3) not placing your credit card or other financial information on your hard drive, 4) using different passwords for every account or application, 5) locking your credit file with the three big credit agencies, 6) running a back up of all your files every day on to a separable hard drive. In the end, however, you really can not stop someone good at hacking who wants to get in.

What's the most insightful question you've been asked by a HKS student while lecturing? That will probably be a smarter question than I can ask.

We discussed the ethics norms that should apply to White House staff, particularly career officers. Do you implement policies with which you disagree? When do you resign because you disagree? Is it ever justified to leak information to the press without higher level approval? These are tough questions.While you may not want situational ethics, having hard and fast rules for your personal conduct is difficult. I think, for example, that HR McMaster is damaging his reputation by defending some of what Trump does, but HR is willing to pay that price to stay in office so that he can prevent Trump from doing something completely crazy. I probably should have quit the White House when it became clear that Bush (43) was not going to do anything significant to fight al Qaeda prior to 9-11, but I stayed thinking that maybe i could change their minds. Later, i quit when it was clear they were going to invade Iraq. That invasion was more than I could stomach. I could not be in any Administration that was doing something so harmful to our country. In this Administration I think people are leaking to bring things to the President's attention in some cases and in other cases to expose potentially illegal actions by the Administration. Leaking is personally risky and in some cases takes a great deal of courage. In other cases, it is just some one trying to feel important or involved. Ideally, you should think these sorts of questions about in your mind in advance of taking White House job. You should know where your red lines are.

What are the most common causes of radicalization, and what can we do to thwart radicalization?

Radicalization in Europe and the Middle East are somewhat different one from the other. In Europe, young Muslims are often disaffected because they feel discrimination by the majority. In the Middle East, the allure is more ideological. The terrorist distortion of Islam is appealing to youth who seek a cause and find none in their own societies. There needs to be an ideological counter-weight, something for people to believe in, something that offers a future better than the past, something they can participate in.

You say here, "...who are the Cassandras and who are the chicken-littles?" Can you please explain this distinction?

Cassandra was right, at least in the Greek myth. The problem was on one would believe her. Chicken Little is a story about someone who was easily scared and misjudged and over estimated the threat or risk. In our typology, Cassandras are recognized experts who are data driven. They are outliers, other experts do not agree. The Cassandras see the risks first. Others catch up later, often when it is too late.