“The question is”

We use two forms for “the question is.” One form is to simply construct a declarative sentence (“The question is how long we should wait.”). Note that the sentence is declarative, so it ends with a period, with no comma after “is.” If you want to end with a question mark, set the sentence up in the second form, with a comma; capitalize the first letter of the question if it is a long question, such as eight words or more (“The question is, how long should we wait?”; “The question is, What should we do to avoid making this mistake in the future?”).