Every new president understandably wants to avoid the mistakes of his predecessors. For President-elect Obama, that means one thing: Make sure you start off on the right foot with that co-equal branch of government at the other end of Pennsylvania Avenue -- Congress.

The last two Democratic presidents stumbled out of the gate on this essential measure of presidential leadership. The most infamous example of White House mismanagement on this score was when President-elect Bill Clinton ignored the then-Chairman of the powerful Senate Finance Committee, Sen. Daniel Patrick Moynihan (D-N.Y.), in the early days of his administration.

"Not since November," Moynihan told Time magazine in February 1993, responding to whether he had been contacted by Clinton or one of his staff. "Not a single call. Not from the president or any of his top people. I would have thought someone would have gotten in touch by now. I just don't get it."

Indeed, the reaction of an unnamed White House official quoted by Time was nothing short of remarkable:

"Big deal," says a top administration official. "Moynihan supported Bob Kerrey during the primaries. He's not one of us ... He's cantankerous, but he couldn't obstruct us even if he wanted to. The gridlock is broken. It's all Democratic now. We'll roll right over him if we have to."

Memo to the President-elect: This is not how you deal with powerful lawmakers on Capitol Hill.

Likewise, Jimmy Carter struck many veteran lawmakers as a sanctimonious rube from Georgia. His White House "Georgia Mafia" never quite settled into a constructive relationship with the overwhelmingly large Democratic majorities of the late '70s. His unilateral attempt to de-fund many pork-barrel federal water projects became the symbol of these missteps.

This time, the new president-elect seems to be saying things will be different. His appointment of Illinois Rep. Rahm Emanuel as White House Chief of Staff is an indication that Obama hopes to create a seamless relationship with Capitol Hill. Emanuel knows three things well: As a senior official in the Clinton White House, he knows the inner workings and demands of 1600 Pennsylvania Avenue; as a former House member, he possesses an intimate knowledge of Democratic lawmakers; and as a Chicago pol, he knows President-elect Obama.

Congressional Republicans, however, may look upon Emanuel's appointment less charitably. Emanuel, after all, demonstrated an unparalleled skill at unseating House Republicans these past four years. He proved especially adept at ending the congressional careers of Republicans in even the safest Republican districts. It's understandable if some in the House GOP regard Emanuel as the Democratic equivalent of Karl Rove with a congressional voting card.

The Senate, of course, is a different story. Republican strength in the upper body will be sufficient to sustain filibusters and therefore thwart ambitious big government initiatives if -- and this is a big "if" -- Senate Republicans stick together.

Obama's challenge in the Senate is actually twofold: 1) find ways to win the support of targeted Republicans on each issue and 2) ensure that the growing rump group of moderate Senate Democrats feels comfortable voting for policies that may be unpopular back home.

The bottom line is that the president needs to view his relationship with Capitol Hill as among the most important diplomatic challenges he faces. Congress can be a witch's brew of egos, turf battles and long memories. Small wonder it often turns into the killing field for many a presidential agenda.

Michael Franc is Vice President of Government Relations at The Heritage Foundation.