Keller: Deaton brought the fire against Markey in Senate debate, but the math is not in his favor

The opinions expressed below are Jon Keller's, not those of WBZ-TV, CBS News or Skydance.

Republican Massachusetts Senate nominee John Deaton is not stupid. He knows he's a massive underdog in his race against incumbent Ed Markey, trailing by a RealClearPolitics polling average of 23 points, a yawning gap that has never shown any sign of closing.

And he can read the national polls too. "We all know that the Democrats are going to win the House, and the Democrats are going to win the Senate," Deaton said in Tuesday night's WBZ debate. "You have a chance to send a nonpartisan person like me [to Washington] who will really put America first and decide, 'Is it good for Massachusetts and America?' And if it is, I'll support it."

This is the choice cut from Deaton's beef with Markey - his argument, aimed at independents and disgruntled Democrats, that Markey is too partisan to be trusted. After agreeing with Markey that Donald Trump's war with Iran is illegal and foolish, Deaton cited military ventures under Democratic presidents that "you never said a word [about] because they wear Democrat jerseys. I wear an American jersey. I call President Trump out, I'll call a Democrat president out."

Unfortunately for Deaton, the math is not in his favor. Mr. Trump's job approval in Massachusetts is at a record low in the most recent polling last month, third worst in the nation. Just 7% of Democrats approve, along with a pitiful 12% of independents. Even among Republicans, approval of Mr. Trump has tumbled to 64%, down from 79% in August.

And by emphasizing his distaste for much of the Trump agenda and his refusal to vote for Mr. Trump, Deaton has even shrunk the available pool of Republican votes, not that they amount to much.

So, it was no wonder that Markey made a run at the world record for disparaging references to Mr. Trump in an hourlong debate set by Gov. Maura Healey just last week. Trump has "declared war on the Massachusetts economy" and "targeted" Markey's neighbors in Malden, he said. And right off the top he cast Deaton as "the elephant in the room," a poseur who "gave $350,000 to the Republican Party in order to buy this nomination. He's got an R on his jersey, he bought that R … He's trying to pretend that he's an independent and that he's a Republican at the same time. That's an oxymoron. It's like trying to be a carnivorous vegetarian, you just can't get away with that."

Ouch.

Deaton was well-prepared, brought the fire, and landed a number of blows that at times appeared to make Markey wince. But the incumbent never took the bait, pivoting away from every taunt with a Trump-related counter.

In this state, this year, with this president insisting voters pretend he's on the ballot, that should be more than enough.