WASHINGTON — Russia is using the waning days of the Obama administration to strengthen President Bashar al-Assad’s hold on power, expand the territory he controls in Syria and constrain the options of the next American president in responding to the civil war, according to a number of American officials and Russian analysts.
The strategy of President Vladimir V. Putin of Russia, they say, is to move aggressively in what he sees as a prime window of opportunity — the four months between now and the 2017 presidential inauguration — when Mr. Putin calculates that the departing President Obama will be unlikely to intervene in the escalating Syrian conflict and a new American president who might consider a tougher policy will not yet be in office.
“Putin is in a hurry before the American elections,” said Nikolai V. Petrov, a political scientist in Moscow. “The next American president will face a new reality and will be forced to accept it.”
American intelligence analysts have told the White House that the Russian goal is to help the Syrian military retake the besieged city of Aleppo so that Moscow can resume talks on Syria’s future on vastly stronger terms, according to administration officials who asked not to be identified because they were discussing classified assessments.
Divining Mr. Putin’s intentions has always been more art than science, but there is every indication that he sees Syria as a strategic interest. Russia’s intervention in the war represents the Kremlin’s most important military foothold in the Middle East in decades and has enabled Moscow to showcase the military’s ability to project power.
The intervention has also enabled Moscow to stand by an ally, Mr. Assad, and to some extent carry out operations against the Islamic State and Nusra Front, the terrorist groups that are the ostensible targets of Russia’s deployment in Syria.
The Syrian military has its weaknesses, including a manpower shortage that precludes it from securing the entire country and which has forced the Assad government to rely on fighters from Hezbollah, the Lebanese militia, Shiite fighters from Iraq and Afghanistan and Iranian advisers, along with Russian airpower. So far the Assad government’s territorial gains have been minimal, even after Russia’s intervention a year ago.
But Russia is trying to help Syrian forces take the rebel-held area of eastern Aleppo in hopes that it will significantly set back the opposition, enlarge the areas that Mr. Assad controls and put the Kremlin in a stronger position to shape the political talks, should they ever resume.
Under this scenario, the Syrian government would control five major population centers: Damascus, Homs, Hama, Aleppo and Latakia.
“It is possible that the end state is going to be something where there is a military stalemate but the regime is in the command position,” said Robert S. Ford, a former American ambassador in Damascus and a former envoy to the Syrian opposition who is now a fellow at the Middle East Institute in Washington. Should the Syrian regime be successful, he added, “I don’t think the opposition will surrender — they are not going to stop fighting — but they will be marginalized.”
Hillary Clinton, the Democratic nominee for president, has previously called for a partial no-fly zone in Syria, which would require substantially more American military action in Syria. Aides to Mrs. Clinton say she has not changed her position on such a zone. As secretary of state, she also supported covert assistance to the rebels to try to put pressure on Mr. Assad to hand over power to a transitional government.
The Obama administration has used airpower to safeguard areas of northern Syria where American advisers are operating, although the Pentagon has steadfastly refused to call it a no-fly zone. After Syrian warplanes dropped bombs in August near American special forces on the ground, the Pentagon warned the Syrians to stay away. American F-22 fighter jets drove home the message by patrolling the area.
But a successful Russia-Syria offensive on Aleppo would redraw the map in important ways and could complicate any plans for further American military action in Syria.
“Russian officials and intellectuals have told me directly that they believe Hillary Clinton would be more likely to use force in Syria than President Obama,” said Andrew J. Tabler, a senior fellow at the Washington Institute for Near East Policy. “The seizure of Aleppo would be a fait accompli for the next American president. The war would go on and the Islamic State would still occupy parts of the country. But the regime would retain the north-south spine of the country.”
This was not the outcome the White House envisioned a year ago when the Russians began to build up their air forces in Syria. At first, the State Department sought to block the deployment by asking Bulgaria and other nations to close their airspace.
But the White House soon concluded that it was pointless to try to stop the Russian buildup, and some officials even thought it might even push Moscow toward a search for a political solution.
Now that talks for a reduction of violence and access to humanitarian aid have failed, the White House has renewed its considerations of military options, including airstrikes to deter the Assad government from trying to take Aleppo. But Mr. Obama has long been wary of getting drawn deeper into the conflict. Other steps the administration could take involve raising the cost to Russia of its intervention, through such measures as economic sanctions.
Some administration officials have argued publicly that Syria could turn into a quagmire for the Kremlin, particularly if the Arab states that support the rebels supply them with antiaircraft weapons and Islamic terrorists decide to retaliate by attacking Russian cities. That, the officials say, may yet lead Russia to rethink its strategy.
“They’re going to be bearing the brunt if the civil war escalates as a result of their actions of an onslaught of weaponry coming in from outside patrons,” Antony Blinken, the deputy secretary of state, told Congress last month.
But so far Moscow has pursued its strategy at a modest cost in terms of Russian lives and treasure, reflecting the hard-learned lessons of earlier conflicts. Unlike in the Soviet Union’s invasion of Afghanistan, Russia has mainly relied on airpower in Syria and has avoided the use of major ground combat units.
Nor does Moscow’s strategy appear to call for the Syrian military to engage in costly street fighting against dug-in rebels. Rather, it has relied on airstrikes by Russian and Syrian aircraft to block deliveries of humanitarian aid, destroy water treatment plants and damage hospitals.
There are also some American actions that may make Syria less of a quagmire for the Kremlin. The American-led coalition plans to continue to target the Islamic State and the Nusra Front, two jihadist groups that pose a threat to the United States and Russia alike.