Starting about 40-years ago political party conventions changed from a gathering to select the party's nominee, to rubber stamping the candidate who won the required amount of delegates during the primaries. That can leave delegates of the vanquished candidates less than fully supportive or even still opposed to the nominee. Paul Brace is a political science professor at Rice University.
“Then the question is: Can the nominee, to be announced, manage the dissenters in a way that allows them to present themselves in the most productive manner for their purposes, notably, seeming to present a unified front going into the election?”
That is why the rules committee has approved a change that would allow the primary winner's campaign to veto any elected delegates. The Texas delegation sees this as a way to stifle grassroots movements and allow for more control by the winners rich patrons.
“It would be centralized control. It would eliminate outside voices.”
Whether or not the Texans can change the rule remains to be seen, but in politics, today's outsiders and dissenters can become tomorrow's power brokers.