The speech was mostly delivered with force, but Rubio at times seemed nervous and cotton-mouthed, patting sweat off his temples a few times and awkwardly pausing to grab an off-camera bottle of water.
That sip caught fire on Twitter and television, and may be what the speech is remembered for.
"It definitely appeared Sen. Rubio was a bit nervous at times, getting dry mouth and finally taking a drink of water," Fox News host Bret Baier said shortly after the speech. Rubio himself took to Twitter to joke about the moment, tweeting a picture of the Poland Springs water bottle he'd taken a drink from.
For more on Rubio's response, click here.