Of course there is. We need to separate intent from action. There's myriads of different actions to achieve the same result.
Imagine this scenario: China postures for military action, the U.S does not intent to interfere. Rather than "abandon it's ally" the U.S puts on a show of strength, joint military exercises, recommitting to the defense of Taiwan, the whole 9 yards. Quietly however, the U.S. withdraws support for secessionist factions within Taiwan, shifting the fragile equilibrium. pro-china factions gain power quickly, the weakening direct U.S support combined with China's military posturing drives moderates and anti-war secessionists towards the pro-china faction. With the balance of power now in their favor, mainland + the pro-china factions ramp up propaganda efforts, strengthening ties, eventually setting the stage for reunification. The U.S of course, while "extremely disappointed", won't oppose the popular will of the Taiwanese people.
And that's how the U.S abandons its ally without abandoning its ally, and China takes Taiwan by force without ever firing a single shot.
Of course, that's just one possible scenario out of thousands. The question here is intent - if the U.S intends to fight China it will for its own purposes. if the U.S doesn't intent to fight China it won't for its own purposes. Countries aren't as beholden to their public image as people think, because there's a million ways to spin anything.