On Thursday, President-elect Donald Trump tweeted that the "United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes."

In the presidential debates, Trump said "Russia has been expanding" its nuclear weapons, adding that it has "a much newer capability than we do."

But according to Jeffrey Lewis, the founding publisher of Arms Control Wonk, although Russia may have updated its missiles and warheads more recently, the idea that Moscow has better capabilities is "almost certainly not true."

Kingston Reif, the Arms Control Association's director for disarmament and threat reduction policy, told Business Insider that the US's nuclear arsenal is "second to none," and that expanding US nuclear stockpiles risks "accelerating and worsening global nuclear competition and the chances of war."

But fears that Russia has surpassed the US in nuclear ferocity are not completely unfounded. On paper, newer, more complicated, and more fearsome weapons constitute Russia's nuclear arsenal.

Russia's RS-24 Yars intercontinental ballistic missile, introduced in the mid-2000s, can strike anywhere in the US with what some report to be 10 independently targetable nuclear warheads.

Russia's liquid-fueled RS-28 Sarmat, or the "Satan 2." @DoctorNoFI via Twitter

These 10 warheads would reenter the Earth's atmosphere at hypersonic speeds — around 5 miles a second. China has developed a similar platform, and the US simply has no way to defend against a salvo of such devastating nukes.

In comparison, the US's Minuteman III ICBM also reenters the atmosphere at hypersonic speeds, but it carries just one warhead and was introduced in the 1970s.

But the question of whose are better is more a philosophical one than a straight comparison of capabilities.

Lewis says that US Strategic Command leaders, who command the country's nuclear arsenal, have said for decades that given the choice between the US's nukes and Russia's, they'd choose the US's missiles every time.

In an interview with Business Insider, Lewis said that the US's arsenal, while it lacks the potential to devastate and lay waste to whole continents, much better fits the US's strategic needs.

Russia's arsenal vs. the US's

A Russian Yars RS-24 intercontinental ballistic missile system drives during a parade in Moscow. Thomson Reuters

"Russians made a really different design choice than we did" when it came to building ICBMs, said Lewis.

"Russia built nuclear weapons that are incremental improvements," he said, or weapons that would need updating every decade or so.

On the other hand, "US nukes are like Ferraris: beautiful, intricate, and designed for high performance," he said. "Experts have said the plutonium pits will last for hundreds of years."

Indeed, the US's stocks of Minuteman III ICBMs, despite their age, are "exquisite machinery, incredible things."

"Russia's nuclear weapons are newer, true," Lewis said, "but they reflect the design philosophy that says, 'No reason to make it super fancy because we'll just rebuild it in 10 years.'"

The philosophical differences don't end there.

"Russians love to put missiles on trucks," said Lewis, while the US prefers land-based silos, which present a reliable target and lack mobility. During the height of the Cold War, the US at one point tried a truck-launched ICBM, but US safety and durability requirements far exceeded that of the Russians, rendering the platform unreasonable.

"If you look at the truck [the US] built for missiles, it's 10 times more expensive. It's radiation-hardened and way less vulnerable," Lewis said. "We gold-plated the thing."

A Minuteman III missile in its silo in 1989. The US takes its nuclear arms seriously and doesn't sit them on trucks or parade them for show. Public Domain The US "can't do things the Russians did because we're not going to put missiles on a crappy truck," said Lewis. Meanwhile, the Russian philosophy relies on sneakiness and achieving a threat without breaking the bank.

"Good luck trying to find it — it doesn't have to be gold-plated," Lewis said of the Russians' idea of missile trucks.

The US "likes things that are reliable, things that can be maintained, things that you have to really train people to do," Lewis said. This difference stems from the people who make up the US military and how they differ from the Russians.

"Non-commissioned officers are the core of [the US] military," said Lewis. "They've been around a long time. That's why we're way better than the Russians, who still have conscripts."

It's that professionalism at the core of the US military that makes America a different kind of world power. The US prefers accuracy over destructive capability.

"We love accuracy," Lewis said — the US's ideal nuke is "a tiny little nuclear weapon we'll fly right through the window and blow up the building." Meanwhile, the Russians would rather put 10 warheads on the building and level the whole city, civilians and all.

"You see it in Syria — that's how they show it off," Lewis said of Russia's air campaign in Syria, where Moscow has been accused of using cluster bombs and incendiary munitions, and of indiscriminately bombing hospitals and refugee camps. This kind of careless and brutal attitude is a defining trait of Russia's military.

For instance, Russia's leaked Status-6 nuclear "doomsday" weapon, a "robotic mini-submarine" that can make 100 knots with a range of 6,200 miles, is a nuclear-armed dirty bomb. The bomb would not only nuke, but also turn the waters around a harbor radioactive for years to come. The US never even considers this kind of devastation, and it doesn't want to.

A briefing slide, captured by Russian TV, of the possible Status-6 nuclear torpedo. BBC

Russia's nuclear ambitions, as shown in its nuclear arms, are "deeply, deeply, deeply immoral," Lewis said.

"That's why [Americans are] the good guys."

How the US deters Russia without 'doomsday' devices

Lewis said the US really can't defend against Russia's most advanced, diabolical nuclear weapons, as "the problem is just that the math never works."

A Russian nuclear ICBM would blast into orbit, turn around, and break into individual reentry vehicles, which would drive toward their individual targets at Mach 23. The US simply can't afford or design a system that would destroy 10 nuclear warheads traveling at that mind-bending speed toward the US.

The US has "never scaled a missile defense to the size of a Russian attack. It sounds like a really great idea on paper, but when you're looking at 1,000 warheads…" he said, trailing off.

Another possible solution would be to destroy the missiles before they exit the atmosphere, but that means shooting them down over Russia, which presents its own problems.

The US has the most advanced missile defenses in the world. But no missile defense system can defend a whole continent from thousands of hypersonic missiles. Missile Defense Agency

Another would be to destroy the missiles from satellites in space, but according to Lewis, the US would have to increase its satellite launches twelvefold before it had enough space assets to protect the country.

Don't get even — get MAD

Former US President John F. Kennedy during the Cuban missile crisis. JFK Library

Instead of spending years and trillions of dollars — and escalating an arms race — the US relies on a doctrine known as mutually assured destruction, or MAD.

Lewis said that in the days of John F. Kennedy, the US puzzled over how to size its nuclear arsenal. The Kennedy administration decided to build enough nukes to destroy the Soviet Union if necessary. The administration named the doctrine "assured destruction," but critics pointed out that nuclear salvos would be traveling both ways, so the more apt name, intended as an insult to Kennedy's policy, was "mutually assured destruction."

"There was no real theory of victory," said Lewis.

Russian President Vladimir Putin once said Russia could destroy the US in "half an hour or less" using its overblown doomsday devices. But the fact is that US Minuteman III rockets that would vaporize the Kremlin seconds later.

The US nuclear triad. Wikimedia Commons

The US finds it most stabilizing to have a nuclear triad, or three varieties of nuclear weapons available at any time. Submarines, land-based silos, and bomber planes all hold nuclear missiles. No attack from Russia could simultaneously neutralize all three. Nothing could stop the US from retaliating, and nothing would.

The US's nuclear weapons are not doomsday devices that would almost certainly initiate the apocalypse.

Precise, professionally maintained, responsibly kept nuclear arms provide the US with a credible deterrent without needlessly endangering billions of lives.