(NewsNation Now) — Russia’s decision to move troops into eastern parts of Ukraine stands to test a potentially powerful partnership: a Moscow-Beijing axis that would line up against the U.S. and its allies.

Then-President Richard Nixon made the stark warning of this potential alliance first during the Cold War back in the 1970s.

Russia and China have backed each other’s positions on opposing a NATO expansion in former Soviet republics and buttressing China’s claim to the self-governing island of Taiwan. Former Deputy Assistant Secretary of State Joel Rubin said the similarities between Russia’s Vladimir Putin and Chinese counterpart Xi Jinping form the foundation of the relationship.

“Birds of a feather flock together, as they say, and they do seem to have a lot of alignment in how they’re going about their business in their regions,” Rubin said on “Morning in America.” “We see Vladimir Putin dismembering Ukraine right now and threatening Europe. And then we see Jinping on the other side, threatening Taiwan on a weekly basis and really making Asia very nervous about where he’s going in terms of expanding China.”

But the relationship remains lopsided. China’s confident rise as an economic and political force contrasts with Russia’s growing isolation and reversion to Cold War tactics of intimidation and bullying.

China’s Communist Party leadership is believed to be watching the U.S. response to Russia’s actions closely for signs of how Washington would behave if Beijing were to move against Taiwan.

China has been dispatching military aircraft and holding threatening war games in hopes of undermining support in Taiwan for the self-governing island’s de facto independence.

“We have to work closely with our allies. This is what’s been very effective, and quite frankly, masterful by the Biden team, in terms of the moment of dealing with Russia is that they have unified us with our allies, unified our western democratic partners in opposition to Russia unilaterally taking over another country,” Rubin said. “That’s going to be the roadmap for the future with Asian allies as well, if China goes forward and goes into Taiwan. That’s something that right now, this test is being watched by Beijing, and Beijing is wondering, how will the West stand up to Moscow? Will it stand up to Moscow? And up to this point, we’re seeing that unity of purpose, which is crucial for the long game in terms of dealing with this rivalry.”

China is not putting its weight behind Russia’s foreign policy gambits, but the frostiness in relations with Washington shows no sign of thawing, said Shi Yinhong, a professor of international relations and director of the Center on American Studies at Beijing’s Renmin University of China.

“I believe that the Chinese government will continue to take care of China itself in the first place rather than take care of Russia,” Shi said. In the meantime, relations with Washington will remain fraught, particularly over the issue of Taiwan.

Beijing blames heightened tensions with the U.S. on what it calls a false depiction of China as a strategic rival.

As of the relationship between Ukraine and Russia has evolved in the more than 20 years since Ukraine has become its own nation, things have changed. More than 40% of all trade is with the European Union compared to just 8% compared to Ukraine.

It’s even starker when you look at the opinions of those born before or after independence in 1991. 87% of those born after 1991 identify as Ukrainian while 21 percent of those born before 1991 call themselves “Soviet people.”

But this does vary by region, 80% of Western Ukrainians want to be economically tied to the EU versus just 26% in eastern Ukraine.