Speaking as someone who was watching the crowd at the rally last night intently (like everyone else I was expecting a full house) the entire energy in the arena changed at about 6 p.m. when it became clear that more people were not entering the BOK Center.

I got in the arena at about 3 pm after getting credentialed, and I'd say about 80 percent of whatever the full crowd ended up being was already inside.

The lower bowl filled mostly up by 5 p.m. or so but the upper level was barren. I kept checking every 15 minutes expecting to see more people, but they never came. I'd wager that between 5:30 p.m. and 7 p.m., when Trump took the stage, no more than 1,000 new people entered.

I feel like the crowd expected that there were thousands of people outside who were just enjoying the festivities (there was music, and food trucks in the rally zone) and then would come in at the last minute.

When it became obvious that was not going to materialize, there was an obvious change in the mood of the crowd. There was more energy in the room for Eric Trump, Tulsa's Sheriff, and Diamond & Silk than there was for the VP and even Trump.

In fact the response to Pence was subdued enough that you could audibly hear the arena speakers turn up twice as loud between Pence's speech and Trump's.

I don't think it helped the energy level that everyone who was in the arena basically had to sit on their hands for four hours until the pre-game speeches began. By the time the president got to the stage, everyone had been inside for half the day already.