Presidents are often only successful to the degree that they can establish good working relations with Congress. Unified government matters little if the party in Congress does not coordinate -- or is even hostile to -- the party in the White House. Historically Democrats, who tend to be more diverse as a coalition than Republicans, have had internal difficulties that have made governing difficult even when they have had unified control of national governing institutions.
The four years of Carter's Presidency and the first two years of Clinton's are prime examples. Their failures were not the fault of Republicans -- though they did not go out of their way to be helpful -- but rather a consequence of their inability to act as a cohesive unit. Teddy Kennedy went after Carter because Carter was too centrist for his tastes, and Democrats had the numbers to pass health care reform in Clinton's first term.
From Today's Papers in Slate comes a few stories detailing how Obama's transition is taking relations with Congress very seriously:
In a front-page piece, the LAT points out that President-elect Barack Obama is making a concerted effort to reach out to lawmakers. In marked contrast to recent Democratic administrations, Obama's team includes several Capitol Hill insiders, including Rahm Emanuel and Tom Daschle, who are using their connections and reputations "to help build sturdy bridges between the White House and Congress." That effort could go a long way to help Obama's oft-stated goal to "hit the ground running," and Democrats may try to pass an economic stimulus bill in early January and have it ready for the president's signature when he takes office later that month. The NYT also takes a look at the Capitol Hill connections in Obama's team and warns that "such close relationships do not mean that tension between Congress and the White House will not break out." There already appear to be some disagreements among Democrats on how big the stimulus package should be.