It's somehow perfect that Barney Frank's first order of retirement, after 32 years as a member of Congress, was to show up at a community reading of Moby Dick in New Bedford, the erstwhile whaling hub in his former district where the book begins. Frank was given the honor of being the lead reader at the Saturday event, which means that it was he, with his notorious North Jersey garble, who got to utter the famous first line: "Call me Ishmael."

That retirement, however, may be short-lived. The day before the reading, Frank's line was a different one: essentially, "Call me Senator." After initially disavowing any interest in an interim appointment to John Kerry's Senate seat, Frank declared Friday that he is, in fact, eager to serve in that role--and he has told Massachusetts Governor Deval Patrick, who will make the decision. Like most things Frank does, this caused a stir: having him in the Senate while, in all likelihood, Scott Brown and Rep. Ed Markey vie for the seat, would almost certainly be more consequential than going with a mere time-server.

When I reached Frank on Friday, he gave the same explanation he had given others for his change of heart: watching the debate over the "fiscal cliff," and seeing that major decisions about spending and taxes had been left to be decided in the next few months had convinced him that he could make a real contribution in a brief interim role in the upper chamber. "March and April will be the most important months in American economic history, and I don't think I'm being immodest to think I could impact it," said.

But Frank went further in our discussion, laying out the exact approach he would advocate. Simply put, he thinks Democrats should push for additional revenue through an increase in the payroll tax for upper-income earners--not just the very rich, but also the near-rich who made out quite well in last week's fiscal cliff deal. With President Obama backing off of his original pledge to raise tax rates on family incomes over $250,000 and shifting the threshold to $450,000, the Democrats left vitally needed revenues on the table. The answer for the next round is clear, says Frank: Get more money out of the exempted swath of income -- from both those whose incomes fall within that window and above it -- via the payroll tax.

"We did not get at taxes between $250,000 and $450,000, which makes it good territory for putting it out for the Social Security payroll tax base…There is a segment of income from people who make between $250,000 and $450,000 who we think could sustain an increase in taxes," he said. "If they had been [hit with an income tax increase] I'd say we don't want to double-hit these guys, but now it's a second cut at the apple for this [income range] in a politically popular way, to protect Social Security rather than taking it out on the old woman in Boston living on $15,000 a year."