Jeb! (Bush) got spanked  in Wednesday night’s GOP presidential candidates’ debate in Boulder, Colorado. This was no surprise, considering his milquetoast image and the millstone his brother Dubya has hung around his pencil neck.

The surprise is that Donald Trump wasn’t wielding the paddle. Jeb! was whacked by Florida Sen. Marco Rubio, who took his old mentor’s feeble attack and stuck it where the sun doesn’t shine. Mr. Rubio was criticized by a Florida newspaper, the Sun Sentinel, for missing more votes than any other senator this year. The newspaper called on Mr. Rubio to “do his job, or resign it.”

It seems an easy line of attack, which is why Jeb! called Mr. Rubio out at his first opportunity.

“Marco, when you signed up for this, this was a six-year term and you should be showing up to work,” he said.

Mr. Rubio was ready, pointing out that many senators, including now-President Barack Obama and Secretary of State John Kerry also missed many votes when running for president. He highlighted Jeb!’s sinking chances, saying, “Someone has convinced you that attacking me is going to help you.”

Ouch. Not only is Jeb! not up to The Donald’s bullying, he can’t even back down a young upstart he helped create. My Big Takeaway from the debate is that Jeb! (Bush)’s campaign window is rapidly closing, and Marco Rubio is emerging as the lone GOP candidate with any chance of beating Hillary Clinton next fall.