If there’s one lasting lesson of the Cory Booker saga over the weekend, it’s that nothing in politics is as clear cut as it seems.

Democrats have been trying all election cycle to make the coming race about the rich paying their fair share, reining in fat cat bankers and helping the 99 percent, with Mitt Romney serving as the foil.

That’s a great strategy — except for when you and/or your Democratic friends need the financial support of the 1 percent to win elections and make money.

Booker is a great example of this political rhetoric running square into political reality.

As Salon’s Steve Kornacki noted Sunday, the Newark mayor’s political rise has been funded in large part by Wall Street types, and his seemingly potent political future will undoubtedly be dependent on them too — in much the same way that other New York-area Democrats rely on the financial industry to fund their campaigns. (Not to mention the fact that, as Booker noted, New Jersey pensions rely heavily on private equity.)

So when President Obama’s campaign attacks Bain Capital for doing what lots of other private equity firms do – buy up companies, make them more efficient (sometimes closing plants and laying off workers in the process) and make money for their investors – it’s shouldn’t be surprising to see Booker speak his mind.

Booker clearly saw it as an affront to an entire industry and not just Bain — or at least the beginning of a slippery slope in that direction. “Stop attacking private equity,” he said, before softening his remarks in a web video later in the day.

The same was the case with Steven Rattner, the former Obama Administration car czar who last week said very much the same thing as Booker — in short, that the Obama campaign’s actions were tantamount to demonizing capitalism, which is, in the words of Rattner, “unfair.”

“I do think to pick out an example of somebody who lost their job – unfortunately, this is part of capitalism, this is part of life,” Rattner said. “And I don’t think there’s anything Bain Capital did that they need to be embarrassed about.”

Booker’s and Rattner’s comments were highlighted Monday in a web video from Romney’s campaign fighting back against the Bain attacks (see above), but they aren’t the only ammunition Republicans have on this front.

Case in point: Bain executive Jonathan Lavine is a top Obama bundler, and he was actually at the firm when GST Steel – the focus of the Obama campaign’s first Bain ad – declared bankruptcy. (Romney was not). Conservatives were quick to cry foul when the GST Steel ad launched last week.

And as The Hill newspaper noted today, Bain is the 19th largest donor to Democratic candidates this cycle and has actually given more to Democrats than Republicans. In fact, according to the Center for Responsive Politics, securities and investment companies have given almost as much to Democrats as to Republicans this cycle.

In other words, there are lots of Democrats, like Booker and Rattner, who are close to this industry. And there are even plenty of Democrats, including Obama himself, who can be tied to Bain in particular.

But that hasn’t stopped the Obama campaign from taking its best shot. After all, this is what he and his supporters have been building towards for a long time: to make Romney out to be a wealthy, out-of-touch corporate raider. And you can’t make that case without Bain.

But it’s hard to attack Bain Capital without risking some collateral political damage. And at least right now, that collateral damage is harming morale among some important Democratic donors.

That’s why we saw such a forceful response from David Axelrod today; the debate over whether Bain is or isn’t on the table in the 2012 election is just that pivotal.