The key passage comes at the end:
"Instead, the optimal opportunity for a peace deal may be a situation in which Putin believes a decisive triumph is not possible, but he can still save face by spinning the outcome as a success. In other words, he needs a story to tell the Russian people about the positive results of the mission. This narrative doesn’t need to be true, but it does need to have truthiness, or a seeming plausibility. And so, to get Putin out of Syria, the United States might need to play along by avoiding boastful claims of a major Russian debacle. In 1989, after the Berlin Wall fell, U.S. President George H.W. Bush deliberately refused to declare the development a win—to avoid complicating the life of Soviet Premier Mikhail Gorbachev.From the same article, this part is notable too:
Putin needs a victory speech. And Washington may have to help him write it."
"According to The Economist: “If America’s Syria-watchers agree on anything it is that the Russian campaign, which has enabled Mr Assad’s forces to make only minor gains, will fail, and thereby encourage Russia to give up on its proxy. That would be a huge boost to the UN-backed peace talks John Kerry, the secretary of state, is brokering, with the aim of replacing Mr Assad with a transitional government early next year.”"