The truth is Coke needs Pepsi. Good old Pepsi: perennially coming in second, and now third, sometimes tasting better but always with worse packaging and that evil Sauron eye for a logo. The existence of Pepsi is what forces Coke to be better. To not get complacent. To continue to innovate, such as with the Coke Freestyle Machine with which, at Kelly’s Roast Beef, I was able to make myself a Coke Zero with Lime and Root Beer monster drink. Even Coke’s missteps — the early response to “The Pepsi Challenge” and the debacle of New Coke — ended up being huge wins for Coke in the long run. In fact, it wouldn’t surprise me if, in 50 years, they finally figured out that Coke owned Pepsi all this time.

Right now, President Obama needs a nice tall glass of Pepsi — in the form of a liberal Democratic opponent. Should you decide to run against Obama in the 2012 Democratic primaries, you’d be doing him and his crew a huge favor. You may not be in to the mood to do President Obama any favors, but this isn’t really about you or him, it’s about America, remember? And does it seem to you that a Tea Party-dominated Republican Party is going to be a fun thing to deal with going forward in the short term? That debt-ceiling brinksmanship is just the beginning. Obama will always give in at the end, to please alleged “independents.” But what about all the people who actually like what Democrats have traditionally stood for? Being a Democrat didn’t used to be diet Republicanism. That was Bill Clinton’s grand idea: Defeat the right by moving to the right. So, congratulations, Clinton was a gifted enough politician to remain in office despite the Vast Right Wing Conspiracy and his own goofy desires, and the Democratic party became the party that’s Not as Bad as the Republicans. Yet somehow many Americans still see Obama as Trotsky Smurf. He needs a Pepsi to show the world he’s Coke.

And this upcoming Presidential Cycle could use some fizzy bubbles. Otherwise it’s looking pretty dour. So far the Democrats’ re-election strategy seems to be that you’ll vote for Obama, whether you like him or not, simply so that the Republicans won’t take over again. That isn’t the type of campaign strategy I’d want to go with. Obama’s other argument for a second term is that he’d like to keep his daughters out of cars with boys. I’m not sure that’s a campaign slogan America can get behind: “KEEP MY KIDS IN GOOD SCHOOLS!”

Instead, how about a Democratic challenge to President Obama from the left? A hard-fought struggle for the presidency would allow Obama to look centrist to those independents he always wants to keep happy. And it would force him to craft a message and market himself better. You know, like Coke does. He could travel the country, debate some lefty wacko and emerge a stronger candidate.

Who would run against Obama, maybe setting him- or herself up for a trip down the aisle in 2016? Except that never works either — no one likes leftovers — so really, it’s just a race to see who fills the 8 p.m. spot on MSNBC down the road. But nevermind that! Every Muhammad Ali needs a Joe Frazier. And every comeback needs a minor triumph to get it rolling. Here are some candidates who couldn’t beat Obama but could maybe make him drink his tears and make him stronger.

Russ Feingold

Not only was Feingold the best member of the US Senate over the last 20 years, he was the only one worth about anything. After the death of good old Paul Wellstone, Russ was a socialist’s dream of what a Democrat should stand for. He didn’t vote for wars. He didn’t vote for health care because it sucked. He’s much too smart to ever run for president. But he’d be perfect for my sinister purposes. Can you imagine changing the conversation from cutting budgets to just totally raising taxes on everyone? Especially the rich? If your company has record profits, the US government should get a taste, just like any good mafia boss. I mean, we could solve America’s deficit problems today if we just cut defense, ended the wars and forced companies to hire Americans or give back billions to the Treasury. Feingold is too good to be president, but he could school Obama on what it actually means to be a fire-breathing, who-gives-a-fuck liberal. Feingold is even more professorial than Obama and just as smart. It would be like an English Department meeting catfight. Like me, Russ actually does want to redistribute wealth in a real way. Like walk onto Wall St., take all their money, and throw it from a helicopter down on the Bronx. Obama could emerge as slightly less willing to do that, keep his “friends” in the hedge funds, fundraise like crazy and win by a lot.

Nydia Velázquez

One of the most dedicated liberals in the House of Reps and my representative in Congress. I’d run against her, but she votes 99% liberal and how much better than that could I do? I’d just be funnier doing it: make some awesome speeches and do some showboating. Velázquez doesn’t really showboat or play to the cameras much — which sets her apart from most of the New York contingent. Of course, there’s no way she’d actually run against Obama. She’s too interested in working hard. And she’s not rich. But hear me out. Rep. Velázquez, who was born in Puerto Rico, could rally at least some of the Latino vote (and Latinos will be deciding all the elections from now on in your lifetime, so get used to it). And she stands for good old liberalism, making Obama seem like the center of all centers. When she eventually loses, she could make a speech about how Obama is the only one who is going to save Latinos from the National Witch Hunt for illegal aliens that will soon be going straight through everyone’s living room at 4 a.m. with Navy Seals or whatever. Obama appoints her National Immigration Czar and maybe gets to keep the non-Cuban Latino vote that would otherwise go to Republican Candidate that runs with Marco Rubio as VP.

Bev Perdue

First-term governor of North Carolina, a state Obama won last election and will probably lose this next time around. And Perdue will probably be defeated for re-election anyway. Her advantages here: She’s got a terrific Southern twang, looks like a librarian. The kind of librarian that could beat you up. She’s seen as hard on illegal immigration and has a record that can be spun for job creation. She uses phrases like “business friendly” in a way that seems genuine. Obama’s allowed himself to be pegged as a job killer; instead of having a War on Libya maybe he should have announced a War on Unemployment. Put Obama up against a genial Democrat and see if it pushes him to be less of a dreary professor and more of a man of the people. Perdue will have the same amount of political experience as Mitt Romney and it’d be tough to go rough on her. It’s clear Obama actually has to be forced to do the right thing (just ask the inmates at Guantanamo) and will say anything to get elected. Let’s make him make more promises he won’t know how to keep.

Matt Damon

Matt’s smart and handsome and doesn’t want to be president. Which makes him perfect. Actors are great politicians, and Damon possesses a boyish charm and that whole killer Bourne Identity side of his personality. He’s practically an Iraq War veteran from that movie Green Zone that no one saw because no one wants to watch PBS “Frontline” with action sequences. Damon could represent the Hollywood Wing of the Democratic Party. His mom is a teacher, so he could run on the whole Working Families platform. Jobs and kids. The media loved the idea of a Trump presidency because he was on TV. Imagine the reaction a bona fide movie star would get. Obama comes out looking like he’s fighting against the big-money Hollywood types — and Damon can hype his movie about playing Liberace’s boyfriend. It’s a win-win for everyone.

Hillary Clinton

Let’s admit it now: We made a mistake and should have made her president. Can we somehow beg her to take over?

Jim Behrle tweets at @behrle for your possible amusement.