As Obama prepares an aggressive public lobbying campaign for his ambitious second-term agenda, Democrats on Capitol Hill are bluntly warning him that he has to do more to engage them if he expects his congressional allies to take a series of politically tough votes.

Interviews with dozens of members of Congress and senior aides reveal frustration and in some cases exasperation that a president who came from the Senate has no apparent appetite for cultivating relationships on Capitol Hill.

These Democrats say they almost never hear from Obama personally, haven’t been to the White House since Rahm Emanuel was still chief of staff and are mystified that the president passed over a popular legislative affairs aide for the job as top congressional liaison. One high-profile Democrat who recently spoke to a group of Hill Democrats came away stunned at their anger toward a president they hardly know.

Take Sen. Jay Rockefeller, for example. While the West Virginia Democrat predicted Obama would reach out more to Congress — “I think that lesson is well learned, ” he said — this chairman of the Commerce Committee and 28-year veteran of the Senate said he had yet to hear from the president since last November’s election. “I’m just new here,” he said good-naturedly.