If Marco Rubio is no longer a contender for the Republican Presidential nomination, but is allowed to retain control of the Rubio delagates at the nominating convention, how will that change future Presidential races and conventions?

I think you are reading into this more long term disruption than it really means.

He can’t get delegates to vote for someone else, he can only bind them to vote for him on the first ballot. So he doesn’t control them as much as he maintains the first round commitment.

The rules change all the time, anyway. It’s not like the GOP is following some structure back to 1860. and there is nothing binding on anyone at this time. The state party officials may very well tell him no.

They are trying to prevent Trump from getting the nomination on the first ballot. If he doesn’t, there are more options for a brokered convention. Apparently, according to NPR, a rules committee that can change the rules meets before each convention.

Who can predict anything about the future of the Republican Party or future campaigns at this point since this one has been so whacked?

From the linked story
“Rubio said, ‘I want my delegates,’ and I said, okay,” explains retired Army Col. Peter Goldberg, Chairman of the Alaska Republican Party.

Goldberg said he consulted RNC officials in Washington, who told him other state parties are consulting their rules in order to decide what to do with Rubio’s delegates.

“They said some are trying to figure it out,” Goldberg said. “Most states are leaning towards giving [Rubio] his delegates.”

If delegates are tied to a candidate until after the first round of voting, then that could mean that there will never be a first round candidate in the future. All conventions become ‘brokered’.

The way I understood it, the current system was put in place after Estes Kefauver went into the [Dem. but the conventions were run similarly] convention with 3.1 million votes and lost to Stevenson’s 78,000 votes. @zenvelo.

I understand that it’s a ploy to block Trumo, @janbb, but these seemingly trivial machinations seem to have a tendency to come back and bite the political parties in the butt.
The stasis in Congress is, IMO, largely due to such short-sightedness. The majority party finds it expeditious create a rule that blocks the minority party from some action.
Reverse power.
Easy fix? Write another shortsighted exception.

It seems to me that a lot of people voted for Rubio and those people deserve to be heard. If those delegates are open to be reassigned to another candidate, all those folks are denied any voice in the election. They don’t just lose their vote but their vote is actually assigned to someone they didn’t vote for. It seems very unfair to me. After the first ballot, if no one has a majority, then fine take another route to select a candidate but on the first vote count the votes for each candidate and see where we stand. If you voted for Rubio, would you want your vote to be counted as a vote for Trump or a vote for Cruz? Hell no, I would want it to be counted as a vote for Rubio. Even though he loses.

Words you will rarely hear me say:

I agree with @Jaxk on this issue. The first ballot the delegates should be bound as their state determined in caucus or election. If anything, it can demonstrate the lack of consensus on the supposed frontrunner.

Things have changed a lot since the 1950s. Back then, many states didn’t even have primaries. And the Dems have changed a lot since then too. That is why the Democrats have Super Delegates who can vote however they want.

There is no visible hope for rescue of the Republican machine. The choices are stark. It’s either get behind the grestest gift the democrats could hope for, or snatch the nomination forcibly from Trump and thereby verify the conclusion of the base that their will is irrelevant. In either case, the only question left is how many House and Senate seats will go up in the conflagration?