Republican presidential front-runner Donald Trump implied in an attack video Monday that former Florida Gov. Jeb Bush (R) is still smoking marijuana, after Bush had admitted to past use four decades ago.

At the Republican debate on Wednesday, Bush admitted to smoking marijuana when he was a teenager, after Sen. Rand Paul (R-Kentucky) accused Bush of hypocrisy for enforcing strict laws that punish marijuana users.

"Forty years ago, I smoked marijuana and I admit it," Bush said. "I’m sure that other people might have done it and may not want to say it in front of 25 million people. My mom’s not happy that I just did."

On Monday, Trump's Instagram account posted a video compiling some of Bush's statements about immigration, the war in Iraq, and birthright citizenship. Trump, who frequently attacks Bush via the use of Instagram video, wrote in a caption that Bush has "been confused for 40 years."

"Are we sure it was only 40 years ago?" the ad says, before flashing Trump's slogan.

Tim Miller, a spokesman for Bush, wrote on Twitter that Trump's Instagram attacks are "running out of steam":

Bush's campaign quickly slammed Trump, citing his lack of detailed knowledge about foreign policy.

"This coming from the candidate who can't remember the names of our biggest enemies around the world. Seems these attacks are running out of steam,” Bush spokesperson Allie Brandenburger said in a statement to Business Insider.

The video is the latest in a series of simple videos that from Trump's Instagram account that have blasted Bush. Earlier this month, Trump posted a video of a woman asleep at one of Bush's campaign rallies and mocked Bush for his "low-energy" style.

Despite Trump's slam on Monday, the current Republican front-runner did not engage at the debate while candidates like Paul, Bush, and former Hewlett-Packard CEO Carly Fiorina discussed the merits of mandatory-minimum drug-sentencing laws, states' rights to legalize weed, and the use of medical marijuana.

Watch the video below:

SEE ALSO: Jeb Bush admits he smoked pot 40 years ago: 'Sorry Mom'

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