AUSTIN (KXAN) — After weeks of American officials warning that an imminent invasion of Ukraine from Russia was coming, President Vladimir Putin officially launched an attack on its neighbor and threatened to go toe-to-toe with NATO in a chilling speech overnight our time.

Ukrainian officials reported tanks and troops were moving across the border into Ukraine while American journalists on the ground reported hearing explosions — believed to be airstrikes or shelling hitting bases and even cities.

In a recorded speech released moments before the start of the attack, Putin seemingly referred to his nuclear capabilities as he threatened anyone who got in his way with “consequences you have never seen.”

To understand all that’s happening now in Ukraine, it’s important to understand its history — and the United States’ role.

Pinball of control

Ukraine was controlled by Moscow under Catherine the Great until World War I, when Poland reclaimed most of the territory. It was then returned to Soviet control in World War II.

In the early 1930s, under Soviet leader Joseph Stalin, the area faced slaughter in the form of famine. Millions of Ukrainians died during that time — which would influence many Ukrainian’s opinions about being controlled by Russia moving forward.

In his speeches, Putin regularly refers to Ukraine as “historically Russian” land. He implies the land was stolen and handed to “puppets” of western interference. He also regularly says the Ukrainian public wants to be part of Russia, which is largely untrue.

The Cold War

The resolution of the Cold War and the dissolve of the Soviet Union are critical to understand if you want to know why President Putin is doing what he’s doing. It’s also good context as to why American foreign policy will be impacted by this crisis moving forward.

“What this current crisis over Ukraine is really about is the American-led democratic hegemony that had spread over Eastern Europe since the end of the Cold War and the collapse of the Soviet Union,” Dr. Robert Moser, a government professor at UT who has been making videos about the U.S., Russia conflict over Ukraine for his high-level foreign policy class, explained.

The Cold War was waged in the decades following the end of World War II as a struggle of power between worldwide superpowers following the defeat of Germany and Japan in 1945. Putin appears to be testing that power struggle again today.

It’s also important to note that during this time period, both Russia and the United States were bolstering their nuclear capabilities — positioning both countries to be nuclear superpowers. President Putin referenced those in a speech Wednesday night American time.

“We can’t forget that we’re talking about a nuclear-armed state, a state with the most nuclear weapons in the world,” Moser said. “And so you do not take lightly any sort of military engagement with a country that has nuclear weapons.”

The dissolve of the Soviet Union

The Cold War ended in 1991 and the Soviet Union dissolved. During that break up of territory, the people of Ukraine overwhelmingly asked for independence and got it.

This is also where American foreign policy plays such a key role in the conflict today.

“The current status quo in in Europe, in particular with NATO, was built by the United States,” Moser said. “The United States has been the leading country in sustaining that status quo.”

Putin has regularly referenced the breaking up of the Soviet Union as a tragedy. You’ll hear experts in foreign policy say he’s trying to rebuild the Soviet Union, as he has indicated many times.

The formation of NATO

In 1949, the North Atlantic Treaty Organization was created between western Europe, the United States and Canada.

Around this time the Soviet Union was staunchly opposed to western influence and assistance, making it difficult for the United States to aid European countries that were hit hard by World War II — deepening the divide between some western European countries and territories under Soviet rule.

But several years after Ukraine was formed in 1991, it joined NATO’s Partnership for Peace and it has since been working to align itself with both the European Union and NATO.

Earlier this month, Ukrainian President Volodymyr Zelenskyy suggested that NATO membership is a distant dream for his country simply because of opposition from Russia and certain members of NATO, not because his public isn’t interested.

If Ukraine becomes a member of NATO, it would have NATO backing and protection — it would make Ukraine untouchable by Putin unless he wanted to start a full-blown war with the United States and its allies.

“Putin would rather alter the composition of the government in Kyiv, so they reorient their foreign policy away from the European Union and NATO, and back towards Russia,” Dr. Patrick McDonald, another government professor at UT, said. “That’s the long-term political goal.”

The Budapest Memorandum

In 1994, Ukraine signed an agreement, but not a treaty, that signified it would get rid of all of the nuclear weapons that had been left on Ukrainian land when the Soviet Union dissolved. There were a lot of them.

Under that deal, Ukraine was supposed to get protection from the United States, Russia and other western allies against threats to their independence, but because this was a memorandum and not a treaty, it’s not a legal obligation (as, for example, Article 5 of the NATO treaty is).

Russia, in particular, has not honored that memorandum.

Russia’s 2014 encroachment

This isn’t the first time in the last decade that Russia has worked to invade Ukraine. In the more memorable history between Ukraine and Russia, Crimea and the Donbas region play a key role.

In 2014, Russia took control of Crimea, a peninsula of Ukraine, and claimed it as a part of Russia — though the western world did not recognize that annexation.

Russia also provoked an attack on the eastern part of Ukraine that started in 2014, which has been bloody and destructive for mostly Ukrainian civilians. Both Donetsk and Luhansk are Russia-controlled as a result of those fights.

Those territories have housed Russian forces in this conflict and were recognized formally by Putin as Russian-backed separatist-controlled regions.