As President Obama zips past the fabled First 100 Days mark in the White House there is one glaring promise he has not fulfilled - bipartisanship in Washington.

But it might be wrong to blame the new president. As he left the Republican Party this week, Pennsylvania Sen. Arlen Specter made the case that the GOP is to blame for the death of bipartisanship in Washington with ever increasing demands for loyalty to a purely conservative agenda.

More than ever bipartisanship -- or the lack of it -- will be up to President Obama.

"Since my election in 1980, as part of the Reagan Big Tent, the Republican party has moved far to the right," Specter said in a statement explaining why he was leaving the party after 29 years.

But Republicans never made a campaign promise of bridging the partisan divide. When the issue came up during the Presidential campaign Sen. John McCain, the Republican nominee, pointed out that he had a record of working across party lines in the senate while the young senator from Illinois did not.

So it was President Obama, making a play for independent voters unfamiliar with his time in the senate, who pledged during his campaign to end the partisanship in the Capital. And on Wednesday night at a White House press conference to mark his first 100 days in office the president spoke as a man who knows he has failed at bringing Republicans and Democrats together.

The president said he is remains troubled by Washington's inability to take a "time-out" from political games fed by a constant reliance on partisanship. "Political posturing and bickering takes place even when we're in the middle of really big crises," he said.

Then the president laid out new rules for bipartisanship. "If I'm taking some of your ideas and giving you credit for good ideas," he said, "the fact that you didn't get 100 percent can't be a reason every single time to oppose my position."

More than ever bipartisanship -- or the lack of it -- will be up to President Obama. He is close to having a filibuster proof majority in the Senate of 60 votes - if he can get Sen. Specter and the likely winner in the Minnesota Senate race, Al Franken, to vote with him while keeping faith with conservative Democrats like Nebraska's Ben Nelson. In this new political dynamic the President has a level of power in dealing with the Senate not seen since the days of Lyndon Johnson. He will be able to create alliances with the Republicans or push them aside as he likes.

And with no need for Republican votes to get his budget and healthcare proposals approved, the President can unilaterally set the terms for any bipartisanship. At the news conference he said Republicans have to understand that he won the last election because American voters rejected Republican "ideas" such as relying on tax cuts for higher income earners to spur the economy.

If the GOP doesn't want to deal with the election result, he said, "we're probably not going to make progress (on bipartisanship)."

That is new approach to bipartisanship from President Obama is hard-ball politics, purely pragmatic but still pretty cold.

In his first days in office he offered a far warmer embrace as he hoped to win some Republican support for legislation. There were invitations to Super Bowl parties. He even made an early trip to Capitol Hill to meet with Republicans. But that effort quickly sank out of sight like a drop in the proverbial ocean of partisan politics.

During the first 100 days that sea of political distrust expanded beyond Washington. On inauguration day about half of Republicans approved of the new President but now it is down to 24 percent. That is a long distance from the 88 percent of Democrats who rank his first 100 days as good to excellent.

At the time of his January inauguration 56 percent of Republicans told a CBS poll that they were optimistic about the next four years with a President Obama. A Gallup poll released the day before the inauguration found that 34 percent of Republicans, along with a majority of Democrats and independent voters, predicted that the Illinois senator to be on his way to be an above average or outstanding President. Most of the Republicans who did not predict outstanding performance before inauguration day still expected a President Obama to be "average rather than subpar."

So, what happened?

At the 100 day mark, 40 percent of Republicans now say he has done a poor or terrible job, according to a recent Gallup Poll. That is way out of line with overall approval numbers for the president. In a recent Fox poll the president has a 62 percent overall approval rating. That includes 26 percent of Americans who say he is doing better than expected and 56 percent who say he is meeting expectations.

And the biggest complaint from the Republican base is about the new President's economic policies. Neither the Wall Street bail-outs nor the stimulus package won positive responses from Republicans who point to massive deficits and the possibility of tax hikes. Unlike Sen. Specter who voted for the stimulus package the president's Republican critics do not see added spending as a cure for the recession.

But that Republican Party is defined by supporters who are insistent on right-wing policies. And that is a shrinking group. A Pew poll shows 51 percent of Americans identifying themselves as Democrats compared to only 35 percent who identified as Republicans. Compare that to 2002 when Republicans and Democrats both had about 43 percent of the electorate.

In the swing states, the 12 states where voting was closest in 2004, the Democrats have since opened a 38 percent to 27 percent advantage in party identification, according to Pew polling.

The bottom line is that moderate to liberal Republicans are leaving the party and taking with them any audience open to bipartisanship. Sen. Lindsey Graham, a conservative Republican from South Carolina, said after Specter's defection to the Democrats that he agrees the GOP is moving to the right.

"Ideologically we are a center-right party," Graham said, "...however for us to have national relevance we have to run and win in blue states. As a party we have to expand our base and diversify our membership while maintaining our fiscally conservative, limited government approach."

President Obama wanted Republican support for his spending plans to prove to swing voters that he is acting in the best interest of a nation in economic crisis. He did not want to get boxed in as a big spending liberal engaged in petty politics. He didn't get that bi-partisan support. There were only 3 Republican votes for his stimulus package and not one for his budget. But now he has Sen. Specter who is pointing the finger of blame for the lack of bipartisanship at Republicans - not the Democrat in the White House.

"The American people do not care which party solves the problems confronting the nation," Sen. Specter said the day he left the Republican Party. "And no senator, no matter how loyal he is to his party, should or would put party loyalty above his duty to the state and nation."

The burden to show a willingness to compromise, to work across party lines now weighs heavily on the Republicans because they are the party losing independent and moderate Republican voters. President Obama gets solid approval ratings without their help. The GOP has to find a way to make themselves relevant and that means finding a way to get the attention of independent voters. They can hope that the President's plans fail but simply dogging the president and saying no is not an appealing agenda.

In last fall's election Americans said they wanted change. The most stunning fact of that campaign was to see that 80 percent of Americans said the country was headed in the wrong direction. That is why they demanded change. Today, after 100 days of President Obama the level of pessimism has dropped by about 20 percentage points with only 57 percent saying the country is headed down the wrong road.

Republicans are in need of a Reagan-type "Morning in America" message that challenges President Obama's appeal to independent voters with optimism, ideas, solutions and faith in the future.

Juan Williams is a co-host of FNC's "The Five," where he is one of seven rotating Fox personalities.