Geopolitics is alive and well in the 21st century. As much as idealists of any number of stripes might wish it to be different, policymakers must live in the real world. Competition, distrust and an overarching international environment of anarchy define that world. Today, the validity of the foregoing can really not be in doubt. Within this context, the U.S. has a major strategic decision to make. Bluntly, the decision is whether defending Ukraine is worth sacrificing East Asia.

As this author has indicated previously, U.S. geostrategic flexibility is currently limited. Beyond the myriad of flashpoints exploding simultaneously around the globe — Iraq, Syria, Israel/Palestine, Ukraine, and the South China Sea — the U.S. is also looking at a yawning debt over the long run which will keep it in a potential fiscal straitjacket (or at least until it decides to get serious about domestic reform). Since the end of the Cold War, the need to pick its battles wisely has never been greater. Like a good chess player, the U.S. needs to understand the full board and how any move that it makes will affect it on the other side. Ultimately, if the U.S. decides to continue its fight with Russia over Ukraine, it is highly likely to be ceding its capacity to appropriately defend its interests in East Asia. It is important to understand why this is the case.

First, the current conflict between Russia and Ukraine is a textbook case of geopolitics. Russia has long considered Ukraine critical to its self-conception, going back to the days of the Kievan Rus. However, state mythology aside, Ukraine is an area of pivotal strategic importance. Not only is access to its Black Sea fleet in Sevastopol (in Crimea) important, but Ukrainian territory was used by the Nazis for part of their invasion of Russia during World War II. This feeds into Russia's historic sense of insecurity. Russia has long asserted that any effort for the West to bring Ukraine into its permanent orbit, through European Union or NATO membership, would be considered a major threat. As far back as 2007, at the Munich Security Conference, Russian President Vladimir PutinVladimir Vladimirovich PutinOvernight Defense & National Security — US tries to deter Russian invasion of Ukraine Blinken decries coordinated Russian destabilizing efforts Biden says team working on 'initiatives' to prevent Russian invasion of Ukraine MORE outlined a position that has changed little in the intervening period of time:

"I think it is obvious that NATO expansion does not have any relation with the modernisation of the Alliance itself or with ensuring security in Europe. On the contrary, it represents a serious provocation that reduces the level of mutual trust. And we have the right to ask: against whom is this expansion intended? And what happened to the assurances our [W]estern partners made after the dissolution of the Warsaw Pact? Where are those declarations today? No one even remembers them. But I will allow myself to remind this audience what was said. I would like to quote the speech of NATO General Secretary Mr Woerner in Brussels on 17 May 1990. He said at the time that: 'the fact that we are ready not to place a NATO army outside of German territory gives the Soviet Union a firm security guarantee'. Where are these guarantees?"

The overthrow of Ukrainian President Viktor Yanukovych earlier this year made this threat seem even more concrete. Whether one agrees or not with the Russian perception that a Western-oriented Ukraine is a legitimate threat is irrelevant. It is a fear they have expressed explicitly for years. All of Putin's actions this year are illustrative of the lengths to which he and the powers that be in the Kremlin are willing to go to ameliorate this fear.

The U.S. leadership should harbor no illusions. If the U.S. wants to reverse what Russia has done in Crimea and now in eastern Ukraine, it must wrestle with just how significant this issue is for Russia. Sanctions aren't going to be enough. Inevitably, the U.S. will need to re-expand its presence in Eastern Europe and the Baltic republics. But even this would not be enough to counter what is perceived in Russian eyes to be an existential conflict. The U.S. will have to arm and maybe train the Ukrainian army to fight back. This means war in all but declaration. Indeed, as recent headlines about possible Russian hacking attacks on major U.S. financial institutions attests, we are already practically in a subterranean war with Russia.

If the decision is made to proceed with confrontation, the U.S. will need to balance this with the need to respond to the vicious rise of the Islamic State in Iraq and Syria (ISIS) and with the increasing bellicosity of China in East Asia. How exactly is the U.S. to do all of these things simultaneously, especially in light of its looming domestic fiscal challenges? Each requires the type of focus the U.S. has seemed incapable of exhibiting in foreign policy for years. It seems far more likely that whatever threat Washington does finally focus on will push the others to the backburner. Consequently, picking which threat to zero in on is of the utmost importance.

Given China's rise in the economically essential East Asia, its growing clout and constantly improving military, it is reasonable to conclude this is a more robust challenge. Further, East Asia represents the locus of the future balance of global power and is thus an arena of far greater strategic concern than Ukraine. If China is able to create a situation where is has a de facto veto over U.S. actions in the East and South China Seas, it will have secured for itself a Sino-centric order. This will have far more calamitous long-term economic fall out for the U.S. than the status of Ukraine.

One key to sound leadership is the ability to decide decisively and wisely. The U.S. faces great domestic and foreign challenges. It has no choice but to eventually address them or it will lose its position in the global pecking order. The problem of the moment is the need to prioritize. The U.S. can stop Russia. It also can stop China. But is it is far from clear whether it can do both at the same time. If it attempts to do so, it is far more likely that it will throw the two together into an alliance of sorts that would prove to be, as this author has suggested before, our ultimate geopolitical nightmare. The choice really is simple: Ukraine or Asia.

The clock is ticking.

Lawson is a contributing analyst at Wikistrat.