The early collapse of the Biden campaign over the last few months has largely spared the former vice president of the scrutiny that a leading presidential candidate usually receives. Now that he has jumped back to the front of the field, it is worth reviewing Biden’s many significant vulnerabilities on foreign policy. Biden’s foreign policy weaknesses don’t receive much coverage because of his extensive foreign policy experience, but it is because he leans so heavily on that experience to promote his candidacy that voters need to know what is in his record.

The most obvious and best-known weakness is Biden’s vote to authorize the Iraq war and his support for the war for several years after that. Related to that is Biden’s absurd fabrication that he immediately became an opponent of the war as soon as it began. Not only did Biden get one of the biggest foreign policy questions of the last 20 years wrong, but he is still trying to pretend that his position was the opposite of what we all know it to be. It doesn’t take a master tactician to realize that Trump would hit Biden on both of these repeatedly. Trump was not really an opponent of the Iraq war, either, but we have to expect the president to be shameless enough to attack Biden for his previous support for the war. Judging from Biden’s fumbling responses on this question in the primary debates, the former vice president still doesn’t have a convincing answer to criticisms of his support for the Iraq war. The Iraq war vote is still relevant today because it was one of the most consequential blunders in Biden’s career and because it is emblematic of his embrace of the foreign policy establishment’s groupthink on a wide range of issues.

That embrace of establishment groupthink is on display again with Biden’s hawkish attacks on Trump over North Korea. Biden objects to Trump’s North Korea policy, which he portrays as being too accommodating. He believes that Trump is too willing to make a deal, and instead he insists on increasing pressure and sticking with the fantasy of denuclearization. Trump’s handling of North Korea has been very poor, but attacking him for being too interested in a negotiated agreement is wrong on the merits and it is lousy politics to boot. Trump’s North Korea policy has failed because it is too inflexible and its goals are too ambitious. Biden proposes to replace that with a more hawkish policy. Like Trump, Biden wants North Korea to carry out substantial disarmament before any sanctions are lifted. That will be a non-starter under Biden just as it has been under Trump. If voters are given a choice between Trump’s phony engagement or Biden’s hawkish rejection of it, they are liable to prefer the former. If Democrats are going to attack Trump on North Korea, it has to be done by showing that his own disdain for diplomacy and contempt for our South Korean ally have fatally compromised the effort to negotiate with North Korea. Biden can’t make that argument because he shows a similar unreasonableness and inflexibility.

The most recent part of Biden’s record comes from his time as a member of the Obama administration, and this is where Biden may be unusually vulnerable. Biden sometimes disagreed with Obama about certain foreign policy issues, but once Obama decided on something Biden naturally got on board with whatever the policy was. That means that he will be saddled with the baggage of Obama’s worst decisions, and he can’t very well tout his disagreements with Obama’s policies without risking the alienation of voters on his own side. For example, Biden was opposed to the Libya intervention in the internal administration debate, but he can’t talk about this without calling attention to one of Obama’s biggest errors. He was recently endorsed by two of the former Obama officials responsible for pushing intervention in Libya, namely Susan Rice and Samantha Power, and that suggests that a Biden administration would probably be staffed by some of the same people that agitated for unnecessary military interventions during the Obama years.

The former vice president famously believes in having “no daylight” with Israel. Trump has shown us what having “no daylight” means in practice: constantly giving the Israeli government whatever it wants, expecting nothing in return, and undermining U.S. interests and international law in the process. Because he has always been such a “pro-Israel” hawk, Biden will be unable to criticize Trump effectively on his Israel policy. He offered up a boilerplate objection to the president’s annexation and apartheid plan, but his unwillingness to criticize the Israeli government publicly means that he will be hamstrung whenever the subject comes up.

Biden was the vice president when the U.S. policy of supporting the Saudi coalition war on Yemen began almost five years ago. Today Biden professes to be against continued support for the war, and he has made some combative anti-Saudi remarks. When he was in a position to influence U.S. policy, there is no evidence that he lifted a finger to stop the Obama administration’s backing of the Saudi coalition. Prior to his current run for president, there is no reason to think that Biden has had a serious problem with the U.S.-Saudi relationship. Like other former members of the Obama administration, he discovered that backing the war on Yemen is a terrible thing only when it became Trump’s policy. Because Biden was a member of the administration that first involved the U.S. in this war, and because there is no sign that he ever disagreed with the policy at the time, he is uniquely ill-suited to challenge Trump over our government’s ongoing support for that atrocious war. Trump’s subservience to Saudi and Emirati interests is one of the president’s greatest vulnerabilities on foreign policy, but Biden can’t credibly attack him when he was part of an administration that started the same policy.

This is not an exhaustive list of Biden’s weaknesses, but they give you an idea of why Biden would have a hard time challenging Trump’s record of foreign policy failures.