Some writers on the left, such as Ari Berman, have been predicting that the choice of Jim Messina as campaign manager virtually ensures that Obama’s reelection campaign won’t be propelled by the same grassroots fervor that lifted him to the presidency two and a half years ago, painting Messina as a liberal-base-disdaining enforcer in the mode of Rahm Emanuel.

So it’s interesting that in an email to supporters — sent my way by a recipient — Messina noted that Obama would be holding a conference call later today with his top grassroots supporters and volunteers, and made the rather ambitious vow that the 2012 campaign would outperform 2008 in “grassroots organizing”:

Today is the beginning of President Obama’s 2012 campaign.

Over the course of the next year and a half, we’re going to show this country the best grassroots organizing in American history — and if we all rally around the President’s vision for changing our politics and our country, we will win.

But we need to start laying the groundwork now so we’re ready when the race hits full speed next year. The President is focused on the job that he was elected to do, and that focus will not waver -- so he needs your help to shape this campaign.

To make sure we start things right, the President asked me to invite a select group of our top supporters and most active volunteers to a special conference call with him tonight.

We’ll give a briefing on our plans for the first few months and talk about how we need you to be involved right from the start.

As Ben Smith notes, Messina has emerged with surprising speed as the public target upon which liberals are projecting their worry that Obama’s reelection campaign will depart from the organizing and energizing principles that made his 2008 victory so remarkable.

Messina’s email to supporters — combined with the planned Obama conference call with grassroots activists — suggest he and his fellow campaign advisers are hoping to tamp this meme down fast.