If you look back at the Bush administration, you can sort it into three parts or, really, four. The first part lasted from the time he was inaugurated until January 2003, when the 108th Congress was sworn in. During all but the first few months of this period, the Democrats had control of the Senate and Bush could accomplish little without working with the Senate Democrats. Of course, we have to distinguish between the pre and post-9/11 portions of this first period because in the post-9/11 period the Senate Democrats (and the press) were easy to roll right over. The culmination of the first period came in October 2002 when Congress gave Bush the authority to invade Iraq. Nothing better demonstrated the ineffectiveness of the Democratic opposition than the AUMF-Iraq.

But the second period, which lasted the full four years between January 2003 and January 2007, was the apex of Republican power. They held all levers of power, could set the agenda in Congress, could avoid all oversight (effective or otherwise), enjoyed an initial wartime high after toppling Saddam Hussein, won reelection, and increased their majorities in Congress. Yet, as early as July/August 2003, when the Iraqi Insurgency began to take shape and the Valerie Plame/no WMD incident came into focus, it was clear that things were not going on a happy trajectory. In 2005-2006 the Bush administration came apart at the seams as they failed legislatively on Social Security, humiliated themselves with the Terri Schiavo fiasco, let New Orleans drown in the aftermath of Hurricane Katrina, and Iraq spun into a cauldron of death and destruction.

The public’s manifest displeasure first became evident in the polls and was ratified in the November 2006 elections when the Democrats took over both Houses of Congress. The last segment of Bush’s presidency was marked by impotency. The Bush administration had no credibility left and no ability to pass its agenda, and the Democratic congress had insufficient unity and power to change the administration’s policies or push through an agenda of their own.

The reason I point out these distinct periods in the history of the Bush administration is because it helps to make clear how the composition of Congress has a strong influence on the power of the administration. Right now, President Obama has very strong majorities. He can get anything he wants through the House of Representatives. In the Senate, he should soon have 59 votes (although, considering Sen. Kennedy’s tenuous health, he will probably be operating with 58 effective votes throughout this congress). Some of the Democrats in the Senate, like Evan Bayh and Ben Nelson, are going to balk at some of Obama’s priorities, making it difficult to reach the magical 60 votes needed to pass legislation through that body. On the whole, the first two years of this administration are going to be marked by the power of conservative Democrats and moderate Republicans in the Senate to block anything they don’t like.

That could easily change after the 2010 elections. If the Democrats pick up, say, a net of five Senate seats, they won’t have to negotiate all their legislation with Ben Nelson and Susan Collins anymore. A successful 2010 Senate election cycle will create a likely apex of Obama’s power in the 2011-2013 period. But, as we saw with Bush, the bloom can come off the rose pretty quickly in the middle years of a presidency, leading to a more cynical public, a more critical press, and, eventually, electoral losses that cripple the president’s ability to lead.

Obama is smart to stress bipartisanship at the outset because if he is at all successful in the Senate we will be less subject to blackmail from the moderate bloc. But that’s the basic dynamic he’ll be working with in the first two years. It will be frustrating to progressives (expect to hear more and more grumbling about doing away with the filibuster) and progressives should not expect that progressive policies will sail past the blockades set up by Evan Bayh, Ben Nelson, Arlen Specter, Olympia Snowe, and others on various issues. Yet, if we do things right, 2011-2013 could be the period when we get sweeping progressive changes. Go back to the 1965-66 period for comparison. That’s what I’m talking about.