Ex-White House hopeful Sen. Rand Paul suggested Tuesday that the GOP establishment shot itself in the foot in 2012 when the Republican National Convention Standing Rules Committee raised the threshold in what is known as rule 40(b).

Under rule 40(b), a candidate for president must win a majority of delegates in eight or more states to be eligible for the nomination. The number of states was adjusted from five to eight in 2012 to prevent Paul's father, then-Texas Congressman Ron Paul, from having his votes counted.

But now that Republicans are desperately looking for another candidate to defeat front-runner Donald Trump, Republicans seem to be saying it's OK to accept a candidate who hasn't won eight states, Paul said.

"In 2012, when my dad was running, they made a special rule that said you can't be nominated unless you win eight states. And then they didn't count his votes," the Kentucky senator explained on MSNBC. "But [it's] interesting now, if you talk to all of the Republican establishment, they're saying, 'Oh yeah, your votes can be counted.'"

"This is a big deal because think about it, Kasich's votes cannot be counted," he added. "Under rule 40b, they should not be counted. And if it was Ron Paul, they were not counted in 2012."

"But this year they want the opposite. So is that a fair interpretation of the rules?" he asked. "See, they tried to exclude my father in 2012 and now it's backfiring on some of the people that would like to see Kasich or Rubio."

As it stands now, rule 40(b) would prevent Ohio Gov. John Kasich and Florida Sen. Marco Rubio from having their names placed into nomination at the convention because neither candidate has cleared the eight state threshold. However, when the rules committee meets just before the convention this July, they can choose to amend the rule or do away with it altogether.

"When you think about it, both Cruz and Trump have a great deal of incentive not to let anybody else have votes," Paul told MSNBC. "However, 110 people are going to be very important. That's the rules committee and they're going to decide what the rules are."

"I think you're going to see a contentious room with those 110 people," he said.