>awhile
As a journalist, Greenwald should be aware of the difference between "a while" and "awhile".
Awhile is an adverb that means "for a while," whereas "while" is a noun meaning "a period of time." Generally, the two-word form "a while" should be used when following a preposition ("I will read for a while"), or with the words ago or back ("a while ago/back"). Awhile should be used to modify a verb ("I will wait awhile") and can usually replace any usage of "for a while."
https://www.merriam-webster.com/words-at-play/awhile-usage