Story highlights Republicans have refused to hold hearings for President Barack Obama's nominee, Merrick Garland

Kaine also commented on Sen. Ted Cruz's suggestion of holding the current vacancy if Clinton wins

(CNN) Democratic vice presidential nominee Tim Kaine is predicting that Senate Democrats will "change the Senate rules" to confirm a ninth Supreme Court justice if Republicans continue to block confirmation of any new appointments.

"I am a US senator. I have a prediction -- this is not a guarantee -- and I'm not revealing inside intel," said Kaine, who represents Virginia.

"I was in the Senate when the Republicans' stonewalling around appointments caused the Senate Democratic majority to switch the vote threshold on appointments from 60 to 51. And we did it on everything but a Supreme Court justice."

"If these guys think they're going to stonewall the filling of that vacancy or other vacancies, then a Democratic Senate majority will say, 'We're not going to let you thwart the law.' And so we will change the Senate rules to uphold the law that the court will be nine members."

So far, Senate Republicans have refused to hold hearings for President Barack Obama's nominee, Merrick Garland, following the unexpected death in February of Justice Antonin Scalia. Democratic presidential nominee Hillary Clinton has not indicated whether she plans to renominate Garland or make a different appointment if she wins the White House.

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