A group of left-leaning Democrats have created a new organization called "Accountability Now," which will sponsor election challenges against moderate Democrats. The group, which has support from MoveOn.Org and the Service Employees International Union, hopes to move Democrats in Congress to the left, so that they will support President Obama's initiatives and respond to the people who elected them.
First: Politics is very local. Many moderate Democrats embrace the center due to their own ideological background and for political necessity. This is true of both parties. Blue-state Republicans and red-state Democrats are often moderates. And their constituents (or "the people who elected them") are moderates as well.
If Accountability Now does not recognize this, its efforts could fail or even backfire (i.e., cause the election of Republicans). Republican candidates could take advantage of discord among Democrats. Also, in order to gain money and other assistance from the group, candidates could "punk" the organization by running to the left during the primaries but then dashing to the center in the general election -- which leads me to my second "thing."
Second thing: Why does the group believe that Obama wants to move or that he will move to the left? I strongly believe that social movement pressure can force moderate presidents to the left or right. Accordingly, I admire the efforts of liberals, including the founders of Accountability Now, who choose to organize around progressive politics. But I have not witnessed broad social movement activity surrounding Obama, and I doubt that one organization can do the work required of many.
According to opinion polls, Democrats (and independents) remain extraordinarily pleased with Obama. Consequently, most liberal activists have done very little in terms of publicly criticizing or pushing him on any issue. Many liberals have in fact defended him or remained remarkably silent even though he has replicated some policies (such as rendition, use of state secrets privilege, etc.) that the Left passionately contested during the Bush administration. So long as most voters remain pleased with Obama, he will have no incentive to move to the left (or right). Concerted pressure might accomplish this goal, but Accountability Now needs help from other progressives.
Finally, during the Democratic primaries, groups like MoveOn.Org and Service Employees International Union proudly supported Obama, whom they portrayed as a leftist dream come true. Now that Obama has grabbed the political center and has even embraced some of Bush's most despised policies, these groups believe they need to push him and other Democrats to the left. Even though they mistakenly assumed that Obama was a leftist, they still insist that they can isolate "real" leftists to challenge moderate Democrats and that their handpicked leftists will then push Obama -- whom they previously believed was a leftist -- to the left. Well, even though I'm cynical, I'll keep my eyes on this one -- and even send a contribution!