According to this poll, only 21% of voters identify themselves as Republicans. That's down from...well, from pretty much whenever you want to measure going back to 1983.
The polling numbers are comprehensively bad for Republicans. On traditional Republican strong points, President Obama is running up big approval ratings: 71% on Iraq, 62% on terrorism in general, 67% on his handling of international affairs, 56% on taxes. In those areas where Republicans have hit Obama hard, they've scored no points. The President gets 61% approval on his slight softening of Cuba policy, and 54% approval for making conciliatory noises toward Iran.
On the other hand, the antic Republican members of Congress are down eight points after becoming a non-stop bitching machine with no real idea what they'd do if they were in charge. (Remember the Republican budget alternative that contained no numbers?) Of those polled, 78% have little or no confidence in the ability of Congressional Republicans to make the right decisions for the country's future.
Conservatives with any sense are declaring themselves independent, leaving the
Republican Party a bastion of idea-free, angry radicalism. There's no one left to speak for the party except the far-right fringe; most of what people see and hear of Republicans is, by definition, immoderate and scary. The true believers who remain are disinclined to do anything but remain ideologically pure, even when that purity makes no sense.
The Republican brand, so popular a topic of conversation just a few months ago, has been successfully re-defined: they're a party of unpleasant whiners. One of President Reagan's great strength was his attractive magnanimity; he compromised freely, didn't sweat the small stuff, and retained his geniality while always inching the ball forward. In contrast, today's Republican Party is dug-in and nearly Maoist in their repetition of ideology. They scream bloody murder about anything the President does or says, the volume turned up high no matter how insignificant the complaint. They compromise on nothing and are insistent that the answers to all our problems are more of exactly what people rejected at the polls last fall.
Republicans aren't going to manage any kid of comeback until they calm down and come up with some positive solutions. For now, they're apparently operating under the same assumption as Democrats during the Reagan Administration, that people support the President because they're ignorant dupes. That's a tough message to sell to voters, and until Republicans come up with something better, they're headed nowhere but down.