Here’s one way a war might start.

KYIV, Ukraine — The large buildup of Russian troops near the Ukrainian border is as clear a sign as any that Moscow is considering using military force to achieve its aims if diplomacy fails. But how exactly hostilities might begin has been something of a guessing game, military analysts say.

One possibility came into sharper focus this week when the second-largest political party in Russia’s Parliament, the Communist Party, proposed that Russia recognize two self-declared separatist states in eastern Ukraine, the Donetsk and Luhansk people’s republics.

The Russian-backed separatists have been fighting the Ukrainian government for eight years but without formal recognition from Moscow. If Russia recognized the states, that could create an immediate rationale for Russian military intervention.

The proposal took a twisted path on Friday, however. First, the speaker of Russia’s lower house of Parliament said it was a “serious and responsible” one that ought to be considered. But soon afterward, the Kremlin signaled disapproval for such a move, saying that it was important to avoid any provocative steps at a moment that was “so tense and so sensitive.”

The two separatist states claim far more Ukrainian territory than they now occupy, asserting their borders to be not today’s de facto front line but the administrative borders of the Donetsk and Luhansk regions.

So if Russia recognized them, they might invite Russia to base troops in their territory to assist in advancing to their claimed borders. This could cloak a Russian invasion as assistance for new allies.

The Communist Party proposal regarding the states suggested that Russia create “legal, interstate relations governing all aspects of cooperation and mutual assistance, including in questions of security.” It added that recognition of the separatist area would be justified to “support guaranteed security and defense for their people from foreign threats.”

Western diplomats say that Moscow has been striving to settle the eastern Ukraine war in exchange for political concessions from Kyiv, including a rejection of future NATO membership and a role for Russian-aligned political parties and politicians in the national government.

Analysts say that helps explain why Russia has long been reluctant to recognize the states; doing so would take away the leverage it has over Kyiv to accomplish these goals that the more ambiguous conflict has provided.