The short answer: It’s unclear.
When the Florida senator dropped out, ABC News analysis put his delegate count at 168, which includes the five delegates he is believed to have won Tuesday night.
The biggest portion of his delegates came from Puerto Rico, where he won 23 delegates, Minnesota, where he won 17, Virginia, where he won 16, and Georgia, where he won 14. In all, he won delegates from 19 states, plus D.C. and Puerto Rico.
Each state has different rules on what their delegates are required to do, meaning there is no one way for them to go.
Certain states could bind the delegates to vote for Rubio on the first ballot of what may end up being a contested convention in July. Others may allow their delegates to do whatever they want – either as a state-wide block or as individuals – now that Rubio is no longer running.
One thing is clear: His former competitors are gunning for those delegates, who are a collection of party activists or local political leaders chosen to represent a portion of a state’s population.
"Marco has 154 delegates before tonight and I think 90 of those are unbound so, yeah, we’re looking to get slates of people elected at conventions to help get more delegates to our delegate account," Roe told ABC News in Houston. "There’s a lot of ways to do that."
For his part, Rubio gave no clear indication of what he wants his supporters, and delegates, to do now. When and if he does, however, they will not necessarily listen to him because their state laws dictate the next moves.