Unless their name starts with Joe or Hillary, that is. For the rest, American Prospect writer Walter Shapiro thinks potential Democratic primary insurgent candidates should start making the case against President Obama now.

He explains in an article addressed to those insurgents:

If you wait until late 2015 to criticize part of the president’s record, your dissent will come across as craven rather than courageous. Think of Hillary Clinton’s awkwardly distancing of herself from the Iraq War in 2008, even though Democratic primary voters knew that she had voted for it in the Senate. Howard Dean rose from nowhere in mid-2003 because he was the only major Democrat running who had been unalterably opposed to the invasion of Iraq from the beginning. Sometimes in presidential politics, when matters more than whether and right from the start trumps being correct right now.

That’s why 2013 is a perfect time to express skepticism about portions of the Obama record. If you say something now with the right tone, it will be perceived as a sincere expression of deep conviction. The longer you wait, the more poll-tested and political your critiques of Obama will be regarded.

This does not mean attacking Obama from the right, he cautions. Rather it is involves pointing out the chasm between the president’s liberal rhetoric and reactionary policies.  Shapiro cites a long list including: National Security Agency surveillance,  targeting the press,  drone strikes, Guantanamo, the sequester, campaign finance reform and the economy.

“[A]ny criticisms of Obama should be delivered in a sympathetic but sorrowful tone. If possible, stress how the Republicans put Obama in a difficult position, but that, under similar circumstances, you would have made different decisions,” Shapiro writes.

He concludes: “[T]here is a void in the Democratic Party waiting to be filled by a credible figure on Obama’s left flank. And if you don’t have the courage to fill it in 2016, trust me, someone else will.”