The traditional measure of success for delivering the rebuttal to the State of Union is simple: Don’t shoot yourself in the foot.

Who can forget Louisiana Gov. Bobby Jindal’s aw-shucks, zombie-like performance in 2009? Or Sen. Marco Rubio’s near fatal attack of dry mouth in 2013 — made even more cringe-worthy by Rubio’s awkward, furtive little sips from a tiny bottle of Poland Spring Water.

By those measures, 37-year-old, three-term Massachusetts Congressman Joe Kennedy did okay. He didn’t screw up Tuesday night. Neither did he soar. Kennedy’s nervousness was an eye opener. But what he lacked in fluidity, he compensated for with passion. (BTW, that smear on his mouth was lip gloss.)

President Trump delivered a sucker punch State of the Union: soft-center open, hard-right close.

Truth aside, Trump’s speech was a success. He effectively spoke to the voters who deserted him over the last 12 months, leaving Trump (at the start of his speech) a historically unpopular president. In the flash polls taken after he closed, Democrats were approving by a 40 to 45 percent range. That's better than usual for Trump.

Calculating the effect and the relevance of an isolated Trump happening has not — to date — been a useful exercise. It’s the trend that matters, the ebb and flow of spectacle. Let’s see where things stand in a few days.

If the job was to leave Democrats feeling good about themselves, then Kennedy got the job done. And, Kennedy didn't so much ignore Republican and conservative voters as much as he admonished the divisiveness that has marked much of the last year in Washington. 

It was a speech that wove the hashtags of the day — notably #BlackLivesMatter and #MeToo — into the larger scheme of economic equity. And while I wasn’t surprised that there was no hint of an original idea in Kennedy’s rebuttal, I was, however, disappointed. I'm not the only one looking for new ideas, and I can't be the only one wondering when these ideas will hit the mainstream. One year after Trump upended political norms, the Democrats are still looking over their shoulders.

Kennedy's speech was emblematic of the party of Hillary Clinton, Nancy Pelosi and Chuck Schumer. How will this party perform nationally in 2018? In 2020?

Would the other young and promising Massachusetts congressman, Seth Moulton, have been able to slap Trump and the Republican Party and simultaneously argue for new Democratic ideas?

That question of Moulton is not relevant to last night. The SOTU response is, after all, a flash in the firmament — just as the big speech is.

But, that question does matter the closer we get to November’s national elections.

If you closed your eyes during Kennedy’s brief talk (it was more of a spirited homily than a speech), you could hear echoes of his assassinated grandfather, Robert F. Kennedy, baring his soul and speaking from his gut on the campaign trail. RFK framed social justice as an existential imperative. A neat trick in 1968.

Soul was not in the original Kennedy tool box. John F. Kennedy wore his clipped Irish charm like a flower in his lapel. His Ivy League diffidence, however, masked a constitution as cold as a witch’s nose.

RFK famously made the journey from backroom strongman to JFK’s irreplaceable shadow. With JFK’s murder, RFK’s newly developed sense of the cosmic became irrepressible.

The politics of emotion were Edward M. Kennedy’s stock in trade, at least on the stump and on Senate floor.

Joe Kennedy’s Fall River speech was his political Bar Mitzvah. His YouTube denunciations of Trump, Paul Ryan, and White Supremacists have bestowed a credibility with millennials, and generations X and Y. Voters vital to the Democrats future — when they vote.  

Picking Kennedy as a fleeting, one-night party spokesman, was — to paraphrase Michael Corleone — a smart move.

What next?