President Obama had made blaming others (e.g., former president George W. Bush, Fox News, Republicans, Wall Street, the 24/7 news cycle, “gridlock,” the tea party, third-party money) into an art form. However, with the collapse of his credibility, this technique will prove a lot less effective.

Jay Carney White House press secretary Jay Carney (Jason Reed/Reuters)

If the student loan bill doesn’t pass Congress (Democrats have rejected proposals to keep the interest rate on Stafford loans from doubling), Obama will blame the GOP. But who’s going to believe him?

If there is no budget deal or if the government shuts down, Obama will blame the Republicans for refusing to increase taxes. But who’s going to buy this?

If there is no immigration reform bill because Democrats want to stick gay marriage into the mix or refuse to go along with reasonable border-security measures, Obama will blame the GOP. But who’s going to believe him?

If he insists the moribund economy is due to sequestration, which is all Republicans’ fault, who’s going to believe that?

Well maybe some die-hard Democrats will, but independents, some Democrats and the vast majority of Republicans will no longer give Obama the benefit of the doubt. After sequester hysteria, the Internal Revenue Service scandal, Benghazi, spying on reporters and the NSA revelations, defenders of the president have gotten burned over and over again. But more important, as reflected in polling, Obama has managed to alienate voters across the political spectrum. Now critics of the president enjoy the benefit of the doubt.

Aside from scandals, other events are conspiring against the White House. We have never gotten a robust recovery (the administration had predicted unemployment would be below 6 percent by now). Obamacare is a mess and is getting worse. (“The Ohio Department of Insurance announced that, based on the rates submitted by insurers to date, the average individual-market health insurance premium in 2014 will come in around $420, ‘representing an increase of 88 percent’ relative to 2013.”)

The president says everything is A-OK; Sen. Marco Rubio (R-Fla.) says:

It is going to be a disaster. So I’m telling you right now there are people watching this program, maybe even people that supported Obamacare, but when they get their premiums in January and they see how much that has increased, or when they get moved from full time to part time, they’re not going to be happy and the president is going to have some questions to answer.

Who are voters going to believe?

The collapse in presidential credibility is made much worse by Obama’s refusal to clean house or to disgorge simple information and by the rampant game of “Who knew?” that prevents the public from knowing precisely who is responsible for which scandals.

No wonder the Dems are down in the dumps and the GOP is loaded for bear.