As the partial U.S. government shutdown enters a second day, and with both Republicans and Democrats firmly entrenched in their positions, any movement from either party to break the spending impasse seems unlikely in the days ahead.

"It looks pretty bleak to me," Matthew Baum, professor of public policy at Harvard University's John F. Kennedy school of government, said in an interview.

The shutdown was initiated after a routine government spending bill saddled with Republican-sponsored provisions to delay parts of Obamacare, failed to win support in the Democratic controlled senate. This forced 800,000 federal employees off their jobs and meant the closure of a series of non-essential government services.

Budget Battle New Mexico

U.S. Post Office letter carrier Jacob Ribald peeks into the window of the Bureau of Land Management office. The door is locked and a sign is posted saying that the site is closed because of the government shutdown. (The Associated Press)

U.S. President Barack Obama has dug in his heels, refusing to sign any bill that would derail his signature legislation. Meanwhile, both sides are locked into a corner, with the Republicans continuing their demands to include anti-Obamacare amendments and Democrats refusing to consider any such provision.

Polls decidedly suggest the Republicans are being blamed for the shutdown. Possibly fearful of a political backlash, the Republican-dominated House has been attempting to pass bills to selectively fund the government to ensure services such as the national parks and veterans affairs remain open. But those efforts have been rebuffed by the Senate.

"It's a political calculation so they can say the Democrats are responsible for keeping the things you care about closed. I just don’t think it’s going to work. I think it’s a pretty naked stunt," Baum said.

On Tuesday, House majority leader Eric Cantor staged a photo-op showing Republicans, ready to negotiate, sitting at a half-empty conference table.

“From the Republican side, they’re talking about Democratic intransigence. The Republicans are all over the press saying, 'We offered a conference committee, they shunned us. Here we are,'" Baum said.

"The Democrat response is, 'For the last however many months we've been asking for a conference committee and you have been rejecting it because you didn’t think you’d be able to sustain the repeal of Obamacare in conference. And now one hour before the shutdown, suddenly you want a conference? Forget it. This is a stunt.'"

Democrats reject 'blackmail'

Republican attempts to delay Obamacare through the spending bill is pure blackmail, Democrats charge. Obamacare is also the law of land, they say, something settled by the results of the 2012 election and upheld by a conservative Supreme Court.

“The argument would go, if you give into blackmail, you’ll just get blackmailed more," Baum said. "From a tactical standpoint, anything that eases the pressure on the Republicans for the Democrats when they feel like they have the upper hand would be bad.”

The Democrats may have no incentive to back down, but the real world consequences of a protracted shutdown could shake things up.

"The one thing that works against the Democrats is that they are the party of the working middle class, much more than the Republicans are, and so their constituents are going to suffer more in the near term," Baum said.

But any damage to constituents caused by the shutdown in the current political climate, is unlikely, for the time being, to push the Democrats to capitulate, Baum said.

As for the Republicans, those who aren't from red states and have to worry about being unseated in the next election may start to get more concerned about the situation, if they continue to shoulder the blame.

"And there's where you might see a crack in the wall," Baum said.

"The only scenario I can see right now that could break this impasse is if the pressure on the non-Tea Party Republicans becomes too intense and they defect. I don’t really know how plausible that is. I know there’s a handful willing to speak and say, 'This is a bad idea what we’re doing.' Are there enough of them who would be wiling to break from the leadership, I don’t know."

Many observers have focused on Republican House Speaker John Boehner and whether he will submit a clean spending bill to the Senate without any anti-Obamacare amendments. With the support of non-Tea Party affiliated Republicans, that bill would likely pass, putting an end to the stalemate. But there would likely be political damage.

"He seems to think that he can't do that and survive as Speaker," Baum said. "It seems not unlikely that he would risk losing his speakership."

But Baum added that if the crisis drags out long enough, "you could end up with a pox on all their houses."

With files from The Associated Press