There was a moment, he says, during the Obamacare negotiations "when a considerable number of us in the caucus, mostly newer and younger members," came to the conclusion that bipartisan talks in the Senate Finance Committee "were essentially a sham and were designed to draw out the process so that the political attack machine on the other side could do its work."
When the discussions dragged on and on, culminating in a party-line vote on the legislation, Whitehouse says, he and the other new Democrats felt vindicated: "That was where . . . a group of us became most mobilized, saying you just can't take some of this stuff at face value."
On the eve of the Obamacare vote, he took to the Senate floor to excoriate the president's opponents, saying they drew support from "the birthers, the fanatics, the people running around in right-wing militia and Aryan support groups." He made reference to mob violence — to Kristallnacht and lynchings.
The speech was widely ridiculed on the right. But when I asked Whitehouse this week if he regretted the oration or considered it prescient, he allowed only "a little bit of both." What commentators then considered signs that the GOP had gone off the rails, he says, look pretty mild compared to the present bearing of the Tea Party wing of the GOP.
In the face of continued Republican obstructionism, Whitehouse argues, Democrats can only succeed if they make a forceful case for their point of view and visit heavy public pressure on the GOP.
It was only public pressure, he says, that forced Republican movement on the fiscal cliff, Hurricane Sandy relief, and the recently passed reauthorization of the Violence Against Women Act.
The Democratic establishment has, in many respects, come around to this point of view. Since his re-election, President Obama has engaged in an outside-the-Beltway, rally-public-opinion approach to a whole host of issues.
But the president's position still requires conciliation on issues that many liberals, including Whitehouse, consider off-limits; his new budget includes cuts to Social Security and Medicare.
And even in the Congressional ranks, figures like Rhode Island Senator Jack Reed, whose seniority place them at or near the top of several key committees, cannot afford to antagonize GOP dealmakers with fiery rhetoric.
Whitehouse is keenly aware of this reality. As a new senator with a safe seat, he knows he is uniquely positioned to be a bulldog. To sink his teeth into the public discussion and drag it to the left.
The task comes with certain benefits: not least of them a rising public profile. But it's not clear that Whitehouse will be able to claim a big, tangible success in the near term.
That owes something to the issues Whitehouse has chosen to engage.
He seems optimistic about joining with Republican Senator John McCain to produce a new round of campaign finance reform. But the push faces sharp opposition in the GOP. And the issue, however important, has never stirred much public passion outside activist circles.
Tax fairness has some populist appeal; Whitehouse has pushed for a "Buffett Rule," which would require the wealthy to pay at the same rate as the middle class. But taxes seem a core issues the GOP is unwilling to surrender, even as it makes accommodations on social issues like gay marriage.