Despite amassing an invasion force of nearly 200,000 troops and thousands of armored vehicles supported by combat aircraft and warships, the Russian military has failed to reach its primary objectives in three weeks.
Russian military planners expected a campaign that would last 48 to 72 hours and lead to a quick Ukrainian capitulation, but Ukrainian President Volodymyr Zelenskyy has led a fierce resistance and major urban centers, including the capital, remain in Ukrainian hands.
Guns supplied by NATO and EU countries have been a critical factor in stalling the Russian advance.
The US gave $1 billion in security assistance this week, and three weapon systems stand out.
The US made FGM-148 Javelins and the Next Generation Light Anti-Tank Weapon (NLAW), designed by Britain and Sweden, have been the terror of Russian troops since the invasion began.
The Russian military doctrine includes tanks and armored vehicles. A US official said Wednesday that 75% of Russia's tactical battalion groups are committed to the invasion.
The Javelin is a fire-and-forget guided missile that is vulnerable to anti-tank defenses.
The command launch unit has the controls and optical sights for day and night use. The operator of the Javelin missile can fire the weapon and then move to avoid being hit by return fire.
A Green Beret assigned to a National Guard unit told Insider that the Javelin isn't cheap, but it's so you won't fire it often.
The honor student is usually the one who gets to fire a live round. The procedures on an empty weapon will be learned by the rest of the class. The Green Beret, who was not authorized to speak to the media, said that even if you don't fire an actual live round, you still master the procedures and sequence of firing.
The Javelin is so effective because of its targeting flexibility.
The Javelin can hit a tank or armored vehicle from a high angle of attack.
Before the invasion, the Russians tried to destroy the Javelin by building cages on top of their tanks. Hundreds of Russian tanks have been destroyed.
The Javelin can strike against a stationary target, like a building. The US special-operations units used Javelins against people in Afghanistan.
The Javelin is very effective against human targets. An anti-tank weapon system worth hundreds of thousands of dollars is not usually thought of as an anti-personnel option.
The former officer spoke because of ongoing work with the US Defense Department.
There is a famous SEAL Team guy who racked up several Taliban kills using the Javelin. It was ideal for the operational environment because of the large distances.
The NLAW anti-tank weapon is supplied by the British. The NLAW is easy to operate and has a 150mm anti-tank warhead that is deadly.
The NLAW can strike targets from above, but its range is less than that of the Javelin.
Despite an overwhelming quantitative and qualitative advantage, Russia's air force has failed to achieve dominance over Ukraine, reflecting what US officials say were Russian misperceptions about Ukrainian resistance and risk aversion among Russian commanders.
Russian aircraft are still active over Ukraine, where they allow Russian forces to take and hold ground, and can attack Ukrainian forces trying to counter the Russian advance.
Ukrainians have relied on man-portable air-defense systems, such as the Stinger missile, to deter Russian fighters from operating over the country.
The US was unable to send its own Stingers until it figured out how to remove classified material from them, which happened after the invasion.
The use of the Stinger against the Soviets in Afghanistan made it famous.
It can hit almost anything that flies below 12,000 feet. The warhead that homes in on the engine is an infrared one.
Regular grunts, national guardsmen, and even militant groups can use it to shoot down multimillion-dollar aircraft because it is light and easy to use.
Both the Javelin and the Stinger are easy to use. The Green Beret said that the CIA taught uneducated people how to use the Stinger against the Soviets in Afghanistan.
The US provided 1,400 and 4,600 security assistance to Ukraine, and on Wednesday they announced 800 and 2,000 more. There are 6,000 AT-4 unguided, man-portable anti-armor missiles in the package.
President Joe Biden said Wednesday that the United States and its allies and partners are fully committed to helping the Ukrainians.