What is Booker afraid of?

It appeared that Cory Booker, just elected to a new, six-year Senate term, was finally ready to bust loose.

The celebrity former mayor of Newark shared top billing at an event Wednesday with a band called Pussy Riot. Onstage immediately after him was a feminist activist who recently staged a topless protest with a message scrawled across her breasts.

But if people were expecting the shaved-scalp New Jersey Democrat to let down his hair, they were in for disappointment. His remarks at the event, a gathering of activists called RiseUp hosted by the media group Fusion, sounded like fortune-cookie messages.

"The biggest thing you can do in any day is a small act of kindness," he inveighed.

And: "The lines that divide us still in this country are nowhere near as strong as the ties that bind us."

And: "Cynicism is a toxic spiritual state that obscures your vision."

And: "There is still a belief that this is a nation of liberty and justice for all."

What is Booker afraid of?

This paradox has puzzled many since he arrived in the capital last year after a special election: He could use his star power to do almost anything, yet he is acting like a conventional pol.

Young, wealthy, African American, charismatic, educated at Stanford, Oxford, and Yale, he was nationally known and a friend of the rich and famous even before he arrived here.

He could be a movement leader or an iconoclast in the Senate, but so far he's settled in cautiously and quietly, perhaps preserving his prospects as a future vice-presidential pick. He's known less for legislative labors than for frequent tweeting and selfies with colleagues.

At Wednesday morning's event, at the trendy Union Market in Northeast Washington, Booker recalled with disgust that when he was dialing for dollars at party offices, "I would see senators who were up in '16, '18, sitting there making fundraising calls. ... For me it was sort of sobering to witness it up close and personal how broken our system is."

Booker, one of the party's most prolific fund-raisers, neglected to mention that he was hosting a Booker for Senate fund-raiser that very evening ($1,000 to attend, $2,500 to "co-host") at a D.C. restaurant. And he's next up for reelection in 2020.

Booker also spoke about his opposition to the Keystone XL pipeline, calling it part of a "critically important" debate. He said he opposed it this week, and "when it comes up again in January I will dig in again and vote no."

What he didn't mention is he was one of the last three Democratic holdouts who hadn't said which way he'd vote on Keystone, until he finally tweeted his opposition over the weekend.

Booker told the RiseUp crowd, as well, that his "party disappoints me regularly," and he joked that he'd like a law saying "nobody in America can tell us what party you're in, you just have to talk about ideas."

Nonpartisan? He's been in the Senate only a short while, but a Congressional Quarterly study earlier this year found that he sided with President Obama's position 100 percent of the time.

Booker is no coward; he once rescued a neighbor from a burning building. But where is the bravery now?

The moderator asked about his claim that America suffers from "sedentary agitation." He backtracked. "Well, I wouldn't say that," he said, though he has, repeatedly.

Booker did show real passion when the subject turned to the criminal-justice system. "We have more blacks in this country under criminal supervision than all the slaves in 1850," he said, noting that he's been talking about reform legislation with Republicans such as Rand Paul and Ted Cruz.

Booker expanded on his criminal-justice ideas during a talk later Wednesday with the liberal Center for American Progress. Reporters followed him from the hall, trying to ask about Obama's immigration order.

As an aide hustled him away, the senator (who declined to be interviewed for this column) offered only a bromide about Obama being "courageous" before hopping into a waiting Suburban.

His campaign for criminal-justice reform is real. But otherwise Booker has been light with legislation and prolific with platitudes.

"I got my B.A. from Stanford but my Ph.D. from the streets of Newark," he told the RiseUp crowd, describing himself as a "prisoner of hope." He quoted Alice Walker and Martin Luther King Jr. And he repeated the hoary saying that "change doesn't come from Washington, it comes to Washington."

That may be true. But Booker isn't bringing it.