Q. According to CMOS, the honorific title First Lady should be capitalized in all instances. Does that mean that the phrase “the president and First Lady” is correctly capitalized?
A. It’s better to get rid of apparent inconsistencies in phrases like this by capping either both or neither. “First Lady” is normally capped to distinguish her from a woman who happens to be first in something: They offered flowers to the first lady in line at the theater. But in a context next to “the president,” the meaning will be clear even without caps. If for some reason you don’t have the authority to bend Chicago style in lowercasing “first lady,” you could change “the president” to “President Obama” to stay strictly within CMOS guidelines.