Boca Raton, Fla.

Mitt Romney made no major mistakes in his final head-to-head debate with Barack Obama here Monday night, and he presented himself as a plausible commander in chief to the millions of voters watching across the country. So Romney achieved his two main objectives coming into the debate and, at least in that narrow sense, he avoided losing the debate.

But Romney was so determined to avoid sounding like George W. Bush that he spent much of the night sounding like Barack Obama. The two men agreed on so many issues – from Syria to drones, from leaving Afghanistan in 2014 to avoiding wars like Iraq – that voters who tuned in seeking a contrast had only a few brief moments to understand the differences between them.