When Rep. Paul Ryan (R-WI) debates Vice President Joe Biden Thursday night, he will be under pressure to repeat Mitt Romney’s victory over President Barack Obama last week–and to prove that he can meet the “commander-in-chief test.” It is a test that Joe Biden has already failed–not just despite his four years in office, but throughout those four years, calling Obama’s own judgment into question in choosing Biden for the job.

Opposed the decision to pursue Osama bin Laden: The Obama campaign has been boasting non-stop about the president’s sole success in office. It has even run an ad–featuring Bill Clinton, who failed to capture or kill bin Laden when he had the chance–suggesting Romney would not have given the order. Yet Biden–by his own admission–opposed the raid. By his, and Obama’s, standard, he is unqualified for the job.

Caused a falling-out in relations with Israel: During a visit to Israel in March 2010, Biden caused a major diplomatic flap by condemning an Israeli government decision to build new housing units in a Jewish neighborhood of Jerusalem. Biden’s rash and over-the-top reaction caused a further deterioration in relations between the administration and the Israeli government, and hardened Palestinian positions against compromise.

Oversaw a corrupt and wasteful stimulus program: When Obama signed the $787 (later $862) billion stimulus, he tried to reassure the public by putting Biden in charge of overseeing the program to make sure the money would be spend in a rapid, “efficient and effective” manner. Instead, the money was spent slowly and wastefully, favoring the president’s political cronies and generating little economic growth or real job creation.

Championed failed and corrupt green energy “investments.” Biden was the Obama administration’s representative at a slew of failed “green jobs” projects, from Solyndra to Serious Energy. Biden defied critics, and the laws of thermodynamics, as he vowed that the Obama administration would not listen to opposition to its “green jobs” agenda–the day before Solyndra announced that it would suspend manufacturing operations.

Failed to secure post-war Iraq. Biden was tasked with leading negotiations with the new Iraqi government to maintain a U.S. troop presence in that country, as suggested by military leaders–and Obama himself. But Biden, who once advocated the partition of the country, failed, resulting in a complete U.S. withdrawal from Iraq–one that left the country vulnerable to renewed terrorism and to the machinations of the Iranian regime.

Waged a one-man “war on women.” On the campaign trail, seeking desperately to live up to his overhyped and contrived “working-class” credentials, Biden repeatedly treated women as sexual objects–touching female fans, canoodling with a female biker, and following up the introductory speaker at a North Carolina rally, arm draped across her shoulders, with the comment: “if I were not married, I’d ask her out on a date.”

Failed to secure a grand bargain on government spending. Biden was the member of the Obama administration assigned to negotiate with congressional leaders in 2011 during talks over raising the debt ceiling. House Republicans actually preferred dealing with Biden to dealing with Obama and his staff. But even Biden could not deliver, as the Democrats insisted on raising taxes to bridge a gap that taxes cannot actually cover.

Inflamed racial tensions for political gain. When Biden warned a largely black audience that Romney would “put y’all back in chains,” it was not a mistake–and Biden has not apologized. It was part of an ongoing strategy, carried out at the highest levels of Democratic Party leadership, to scare blacks into voting by associating Republicans, falsely, with Jim Crow laws, slavery, and other painful historical memories of racism.

These are just glimpses of what a Biden presidency might mean. And they are not just a reflection on the president’s running mate, but the president himself. When Biden was nominated in Aug. 2008, he was touted by the race-obsessed media as an ideal choice, a grey-haired white man to soothe supposed fears of Obama’s blackness, and one who also brought decades of foreign policy experience to fill a key gap in Obama’s resumé.

What the media ignored was the substance of Biden’s experience: he had been wrong on every major foreign policy issue he encountered. His signal achievement had been turning judicial selections, à la Robert Bork, into ideological litmus tests. Now that Biden has an executive record by which to judge him, Ryan should not let Biden–or Obama–off the hook when he takes the stage at Kentucky’s Centre College on Thursday night.