The debate over providing “fast track” authority for President Barack Obama to negotiate the Trans-Pacific Partnership (TPP) and other trade deals has touched on constitutional, economic, and political arguments. Yet the most important question is whether Obama should be allowed to negotiate anything at all after a dismal track record. When Obama is negotiating with anyone other than congressional Republicans, who fold easily, he makes one bad deal after another.

1. ‘Boneheaded’ Tony Rezko land deal, 2006. Barack Obama knew who he was getting into bed with when he bought his house on the same day that the wife of his fundraiser, Tony Rezko–now serving time in federal prison for fraud–bought the parcel of land next to it. Later, Obama bought part of that land for his own yard. When the transactions were exposed, Obama admitted that the deal had been “boneheaded.” He later gave some of Rezko’s campaign donations to charity.

2. New START treaty, 2010. As part of the failed “reset” policy, Obama pushed for a new arms control treaty with Russia–a deeply flawed agreement that placed the disproportionate burden of weapons cuts on the U.S. and lacked adequate verification. Russia promptly insisted that the deal precluded U.S. missile defense, and Obama put up little resistance. In fact, Obama he new cuts in 2013–even though he was aware Russia was cheating on existing arms deals.

3. China climate deal, 2014. Obama touted his success in a deal with China that would require the U.S. to reduce its greenhouse gas emissions now–and that would allow China to increase its emissions until 2030. The deal followed a 2009 effort at the UN climate change conference in Copenhagen in which Obama made no impact whatsoever. His own allies on the issue were bitterly disappointed with a “toothless” deal that Obama insisted was an “unprecedented breakthrough.”

4. Cuba deal, 2014. After his party endured historic defeat in the 2014 midterm elections, Obama defiantly announced a new thaw in relations with Cuba–one in which the concessions were almost entirely on the American side. The Cuban regime continued much as before, with its repression of political prisoners and dealings with America’s enemies. Critics noted that Obama had promised in 2008 not to normalize relations with Cuba until all political prisoners were released.

5. Iran deal, 2015. When he came into office, the world was united against any Iranian nuclear enrichment whatsoever. Obama undermined that unity in his desperate search for a deal–one that, by his own admission, now provides Iran with a path to an eventual nuclear weapon. The final deal, due June 30, still has no provision for inspection of Iran’s nuclear sites and military sites, and the Obama administration is covering up Iran’s violation of nuclear sanctions to preserve the farce.

So why would we trust Barack Obama to represent our interests abroad without any way to scrutinize what he is doing?

Republican leaders have failed to answer that question–or to gain anything in return from Obama for defending him.