From the American constitutional experiment in 1788 to World War I, the United States strenuously avoided being dragged into Europe’s conflicts.

However, after the second and even more cataclysmic European war, caused in part by the first conflagration and America’s entry into it, the United States jumped into European affairs with both feet. Intoxicated with its victory over the Nazis and paralyzed with fear about the exaggerated threat from an also victorious, but devastated, Soviet Union, U.S. leaders provided security guarantees under NATO for the defense of Western Europe during the Cold War.

After the Cold War ended, as a weakened Soviet Union retracted its empire from Europe and collapsed, and despite the former Yugoslavia not being in even the expanding NATO security zone at the time, the United States was dragged into the civil wars in Bosnia, Serbia and Kosovo in the mid- to late-1990s. The weakened Soviets could not do much about these U.S. military interventions. Then NATO later continued to expand right up to Russia’s borders.

In 2014, after the United States helped overthrow an elected pro-Russian government in strategic—at least for Russia—Ukraine and replace it with a Western-friendly government, Russian President Vladimir Putin invaded Ukrainian Crimea, annexed it because the headquarters of the Black Sea fleet was there, and backed a Russian-speaking separatist movement in the Donbas region of that country.

As the Biden administration reaffirmed George W. Bush’s foolish pledge in 2008 to admit Ukraine and Georgia into NATO, Putin lashed out with a full-blown invasion of Ukraine’s Crimea. There is no excuse for Putin’s brutal invasion of another sovereign nation (just as there was no valid justification for Bush’s invasion of Iraq in 2003). Yet, the United States’ continued entanglement in Europe’s security issues, and in Ukraine in particular, and its ignoring of legitimate Russian security concerns has ensured some U.S. and NATO culpability, through comparative negligence, for Putin’s reprehensible actions.

What is done is done, but now that the United States, NATO and the European Union are heavily arming Ukraine to try to crush Russia’s economy by imposing harsh economic sanctions to motivate a Russian withdrawal from the country, the major cautionary note should be to avoid the West’s escalation with a nuclear-armed power. Any triumphalism by the West that the incompetent and hollow Russian military is performing poorly vis-à-vis a vastly outnumbered and outgunned Ukrainian military should be tempered by a realization that the more poorly the Russian armed forces perform, the more Russia would be prone to escalate nuclear weapons.

For the moment, President Biden is vehemently rejecting actions that would risk direct conflict between Russian and U.S. and NATO forces, which could potentially escalate—for example, the insertion of those Western forces into or around Ukraine.

Yet, when any great power floods a friendly or allied country with weapons and money (totaling more than $50 billion to date), it develops a stake in the conflict, thus opening the door to escalation when its ally either starts faltering on the battlefield or is so successful that it could push the enemy back; either could happen to Ukraine.

Also, despite Biden’s current opposition to involving U.S. forces, a few proposals recently have surfaced that could do just that.

Adm. James Stavridis, former NATO commander, has floated a proposal to have NATO navies, including the United States, escort Ukrainian merchant ships through the Russian blockade of the Ukrainian coastline. Another by former Republican congressman Joe Scarborough of Florida would take proposals early in the war for a no-fly zone over Ukraine and apply them more narrowly to humanitarian corridors to protect Ukrainian civilians in Western Ukraine.

The first proposal risks naval combat with the blockading Russian vessels, similar to when President Ronald Reagan got into an undeclared naval war with Iran by escorting Kuwaiti tankers through the Persian Gulf in 1988 during the Iraq-Iran War; the main difference now is that Iran was a developing country with weak armed forces and Russia is one of the two most potent nuclear powers on earth.

The second no-fly zone proposal hasn’t been improved that much from similar dangerous proposals to impose such a zone over the entire country at the beginning of the conflict. Although Russian air power has not performed well during the conflict, that is not the point. Even if NATO air power was superior, or even dominant, as it might be, any accidental hostile interaction between NATO and Russian aircraft could trigger escalation. Also, what happens if Russia fires cruise or other types of missiles into the no-fly zone in western Ukraine, as has already happened? Western retaliation in Russian-held eastern or southern Ukraine and escalation?

The final flashpoint is some distance away from Ukraine entirely. Russia alleges that Lithuania is trying to blockade supply trains to Kaliningrad, a noncontiguous area of Russia surrounded by Lithuania, Poland and the Baltic Sea and is the headquarters of the Baltic Sea fleet.

Lithuania lamely rejects this notion by saying it is merely enforcing European Union economic sanctions against Russia. But because such measures are being phased in, not much Russian trade through the Kaliningrad enclave has been halted—yet.

If the EU sanctions grow tighter, as planned, Russia could legitimately fear that the West is trying to impose a blockade on part of its country. Russia has already accused the EU of violating its commitment to unimpeded trade between the two parts of Russia. Although some Russian forces have been transferred out of Kaliningrad to Ukraine and NATO forces in Lithuania have been beefed up slightly, the escalation potential comes from Lithuania being a member of NATO. If Russia tried to threaten or take military action to loosen the effective blockade, Article V of the NATO treaty’s mutual defense pact could be triggered and the dogs of escalation unleashed, including the use of nuclear-capable Russian missiles housed in Kaliningrad.

It is now a given that the United States has committed to a robust effort to help the Ukrainians in their defensive war against a foreign aggressor. However, the Biden administration should continue to be cautious in these three potential flashpoints to avoid escalation because it should remember that U.S. security interests in Ukraine are limited, and the consequences of escalation could be cataclysmic.