Paul Ryan, introduced to the country last year as something of a boy wonder, is going through a rough patch.

A new Rasmussen poll shows that Ryan’s approval rating has plunged to 35 percent, down from 50 percent last August, soon after he was tapped as Mitt Romney’s running mate. What’s more, only 52 percent of Republicans view him favorably.

Now, you have to take those numbers with a grain of salt. I doubt most people are sitting around thinking about how the Wisconsin congressman is doing. His sinking approval is undoubtedly a thumbs-down on how the GOP is handling the endless budget mess. And among Republicans, Ryan is clearly suffering from disappointment that he did little to boost the Romney ticket last November.

Still, his image has clearly taken a hit, and it’s worth examining why.

As I watched his CPAC speech last week, I was struck by what a narrow, green-eyeshade approach he took. While Ryan kept saying he wanted to improve people’s lives, he was cranking out the same doomsday rhetoric about how the Obama administration’s spending would lead to skyrocketing interest rates, government printing presses cranking out money, a plummeting dollar, an unraveling economy, and a shredded safety net. It was a joyless speech that ignored the advent of $85 billion in automatic spending cuts and the president’s push for a grander bargain on spending and taxes.

Ryan had always enjoyed a reputation inside the Beltway as a wonky truth teller, one of the GOP’s intellectual leaders. But now, writes The New Republic’s Noam Scheiber, “he’s made it hard for political reporters to take him seriously.”

The process began during the campaign, when the VP nominee repeatedly attacked the administration for raiding $716 billion from Medicare when his own budget had done the same thing (but applied the savings differently). Ryan made other misleading statements, such as in the convention speech when he faulted Obama over the shutdown of a GM plant in his hometown of Janesville—which, as it turned out, closed before Obama became president. Rather than emerging as a full-fledged personality, he did few national interviews and seemed muzzled by the Romney team.

Now the House Budget Committee chairman has made no one happy with his latest fiscal blueprint, which his party has embraced. For one thing, the Ryan budget pockets the Obama Medicare savings and the tax hike on the top 2 percent that he railed against during the campaign. He again turns Medicare into a voucher program, a position he had to stifle in 2012, because Romney did not approve.

For another, Ryan again calls for the repeal of Obamacare, which is a Republican fantasy at this point.

Beyond that, the budget plan is an amalgam of spending cuts that would hurt the poor and tax breaks—lowering the brackets to 25 and 10 percent—that would disproportionately benefit the wealthy. It is, in short, the same old dog-eared Republican playbook with nary an acknowledgement that Obama just won reelection.

Even conservative CNBC commentator Larry Kudlow was skeptical of Ryan’s accounting gimmicks, asking him, “Does this interfere with a possible compromise with the White House? Are you kind of putting a stick in the president’s eye?”

Ryan emerged from a recent lunch with Obama saying it was the first substantive conversation they’d ever had. But if he is serious about negotiating with the president, it isn’t evident from his austere budget or his red-meat rhetoric at CPAC.

Ryan exuded Midwestern earnestness when Romney picked him, and the press gushed over his P90X workout regimen. There was even talk that he could run for the top job in 2016 if Romney fell short. You don’t hear much of that chatter anymore.