It is right for the American political class to be focused on the July 25 call between President Donald Trump and Ukrainian President Volodymyr Zelensky, and the broader campaign by the president's administration to subordinate the foreign policy of the United States to his reelection campaign. But our leap into an impeachment inquiry is surrounded by important context that the heat of the moment threatens to sweep under the rug.

Today, as our country becomes consumed by the way Trump has corrupted the US–Ukraine relationship, it’s vital to stop and consider why Ukraine matters so much to the US, and why Trump’s purposeful abandonment of Ukraine has been so damaging to our own national security interests.

In 2013, I was a brand-new senator from Connecticut when Sen. John McCain approached me to ask if I wanted to travel with him to Ukraine. There was a popular protest movement brewing that sought closer relations with the West and an end to the endemic corruption that had plagued Ukraine since gaining independence from the Soviet Union. McCain argued this was the moment for a strong message of bipartisan support from the US. While we were decades apart in age, McCain and I shared a passionate belief that the US has a moral responsibility and national security interest in supporting democratic movements and opposing corruption abroad. Vladimir Putin had worked hard to keep Ukraine under his thumb, but now people were demanding a real democracy and a chance to break away from Russia’s grip.

When we arrived in Ukraine, we told the crowd of over 200,000 people at Kyiv's Maidan central public square that we stood with them in their demand for an end to the Russian-orchestrated corruption that had hobbled their country and allowed Putin to control its political destiny.

But it quickly became clear that Putin wasn’t going to let Ukraine go without a fight. The protesters were successful in removing the Putin-aligned government from power; but, in 2014, Russia invaded Crimea and then eastern Ukraine with a goal of weakening Ukraine to the point that it would be forced to realign itself with Russia.

This was a critical moment. A G8 member country had invaded another sovereign nation, all because that country wanted a future with Europe and the US. Then-president Barack Obama knew that this act of naked aggression could not stand, and with bipartisan congressional support his administration mounted a coordinated response to halt Russia’s advance before Ukraine fell back into Putin’s orbit. Obama set up a multibillion-dollar fund to expand the presence of the North Atlantic Treaty Organization (NATO) in Eastern Europe, sent military equipment and US forces to Ukraine to train its troops, provided loan guarantees to prop up the Ukrainian economy, and rallied the world to impose crushing sanctions on Russia for its moves in Ukraine.

In many ways, the election of Zelensky was the result of the US’s unprecedented, bipartisan campaign of support for Ukraine. Parts of Ukraine are still occupied by Russia, but the economy is stable and elections are free. Russia had hoped to be able to cripple Ukraine so badly, and penetrate its political system so comprehensively, that Ukrainians would just give up and elect a president who would link Ukraine back up with Russia. What it got in Zelensky was its worst nightmare: a passionate pro-Europe, pro-US reformer who sees Ukraine’s future with the West.

But Trump was willing to throw away all this progress and abandon Ukraine to the Russian vultures who circle its perimeter, just to score a few points against his political rivals.

The US is now consumed with a developing scandal over the corrupt requests Trump made of Zelensky to help destroy the Bidens and Clintons. But that is just the tip of the iceberg — since the beginning of his term, Trump has engaged in a systematic campaign to weaken Ukraine and destroy the ties that bind our two countries together. This is the missing context for the current impeachment debate.