His chart certainly bears this out:
But there's more to the story than just this. Here's the chart redrawn (you'll need to click on it to see it properly, natch):
and here it is again with a new data point added: the proposed spending cut/tax increase balance proposed by Obama himself:
Much as I think the reason the talks have collapsed is entirely due to Republican intransigence and cupidity, there's plenty of reason to dislike what Obama's doing as well. Republican voters might be more like Democratic voters than they are their own party's politicians, but it's just as worrying that, at least on this issue, the Democratic president is further to the right of Republican voters than Republican voters are of independents ones.
I'm not sure there are many things that display more convincingly how much American politics basically boils down to a bunch of reasonable stooges for the rich battling the thoroughly unreasonable stooges for the rich.
Hell of a country.