During the president’s recent encounter with Vladimir Putin in Vietnam, he says he asked Putin whether Russia had meddled in the U.S. elections in 2016.

He relates that Putin “is very, very strong in the fact that he didn’t do it. You have President Putin very strongly, vehemently, says he has nothing to do with that.” The president also told reporters that Putin “said he absolutely did not meddle in our election” and that “I really believe that when he tells me that, he means it.”

My Vietnam experience was quite a bit different than the president’s. When I was in Vietnam in 1968-69, I represented defendants in about a dozen courts martial. My real job was coordinating artillery fire, but when the defendants learned I was a bono fide lawyer they often requested me as defense counsel. It did not take long to learn that accused individuals often lie about their guilt of wrongdoing.

And, it is not unusual for a guilty person to “vehemently” deny something. When dealing with an accomplished liar, like Putin, one should exercise great caution in believing anything he says. Remember, President Putin denied having any involvement in the take-over of Crimea, the insurgency in Ukraine, and the downing of the Malaysian airliner over Ukraine. All were gigantic whoppers. This former KGB officer is a master of deceit. Anyone who doubts it should read the meticulously documented book by Karen Dawisha,Putin’s Kleptocracy. It is hard to fathom the evil and dishonesty of this man.

It is also unwise to trust the protestations of a man who has been bent on challenging U.S. interests at practically every turn. He has worked very hard to break up a number of important western alliances, including NATO and the European Union. Mitt Romney correctly called Putin’s Russia our “number one geopolitical foe.” During my Vietnam service, I would not have been much inclined to trust the word of the Viet Cong and there is no reason to trust Putin. And, let’s not forget that Russia provided the sophisticated anti-aircraft weapons that shot down John McCain and so many other American pilots.

It is difficult to understand why one would place faith in the word of a known adversary, like Putin, that he did not meddle in our elections when our intelligence people caught him dead to rights. He has also done so in the elections of many of our allies. British Prime Minister Theresa May had the guts to call Putin out for spreading fake news and interfering in that country’s elections. She told Putin that Great Britain would “do what is necessary to protect ourselves, and work with our allies to do likewise.” I’m hoping she’ll help protect us because it does not appear we are doing much to protect ourselves.

The president says he needs to be nice to Putin to gain his help on various issues. Sucking up with an adversary in hopes of gaining favor is not a winning strategy. It is hard to picture Ronald Reagan meekly telling Gorbachev that, while your Berlin wall is attractive and quite effective in imprisoning millions of East Germans, wouldn’t you please consider some slight alterations? Instead, Reagan forcefully said, “Mr. Gorbachev, tear down this wall.” President Reagan’s strength carried the day and the wall came down. We need that same kind of strength in dealing with Putin. Why ask Putin whether he did something we have proof that he did. Let’s follow the lead of PM May--tell Putin we have the goods on him and that he will rue the day if doesn’t bring it to a screeching halt.

Rather than disputing the indisputable, the U.S. should be vigorously building its cyber defenses and developing a tough offensive capability. We are at a juncture in the electronic era much like we found ourselves in during the infancy of the rocket age. The Russians caught our attention with the launch of the Sputnik, demonstrating they had the lead in a technology with military applications. We had to up our game in that arena. Now, the Russians have shown their expertise in the offensive use of cyber systems and it is incumbent on this country to take steps to counter Russian cyber aggression, not to deny it.

Jim Jones is a former Idaho attorney general and a former Idaho Supreme Court chief justice.