Barack Obama has never made a secret of his determination to reach a deal with Iran regarding its nuclear program. Very early in his run for the White House, he announced that he was prepared to meet, without preconditions, with the rulers of Iran and other hostile regimes. “I think it is a disgrace that we have not spoken to them,” he said during a 2007 debate with Hillary Clinton. As president, Obama’s outreach to Tehran began on Day 1. “We will extend a hand,” he promised in his inaugural address, “if you are willing to unclench your fist.” By 2011, he had dispatched then-Senator John Kerry to open a secret dialogue with Iran.

It has long been clear that Obama envisions a grand nuclear bargain with Iran as a cornerstone of his presidential legacy. “It’s my name on this,” he says. “I have a personal interest in locking this down.”

But the terms of that bargain haven’t been so clear. Far from being “locked down,” the goals and guarantees of the Iran nuclear deal have been a moving target. In one critical area after another, the nuclear accord so enticingly advertised doesn’t resemble the nuclear accord actually on the table. When unscrupulous merchants do that, it’s called bait-and-switch. The seller may clinch the sale, but customers resent being conned.

Similarly, while Obama’s nuclear deal will almost certainly survive a congressional vote of disapproval, public skepticism runs deep. A Pew Research poll released Tuesday found just 21 percent support for the agreement. Gallup reports only one in three Americans approve Obama’s handling of US policy toward Iran. That’s not typical — the public usually backs presidents on arms-control agreements. But voters don’t like being conned any more than shoppers do.

How has the administration engaged in bait-and-switch on the Iran deal? Here are five ways.

Inspections. The White House claimed any agreement with Iran would supply international weapons inspectors with the ultimate all-access pass — round-the-clock authority to enter any suspected nuclear site. In a CNN interview in April, Obama’s deputy national security adviser, Ben Rhodes, confirmed that “under this deal, you will have anywhere/anytime, 24/7 access as it relates to the nuclear facilities that Iran has.” When a leading Iranian general scoffed at the suggestion that foreigners would be permitted to investigate possible nuclear activity at Iranian military sites, the Obama administration pushed back. “We expect to have anywhere/anytime access,” Energy Secretary Ernest Moniz reiterated bluntly.

But in the final accord, “anywhere/anytime” is nowhere to be found. The administration claimed it had never existed. (Switch!) “We never sought in this negotiation the capacity for so-called anytime/anywhere,” Rhodes told CNN’s Erin Burnett. Secretary of State Kerry went even further. “There’s no such thing in arms control as anytime/anywhere,” he insisted. “This is a term that, honestly, I never heard.”

Sanctions snap back. The administration acknowledged that stiff economic sanctions had brought the Iranians to the negotiating table. It repeatedly assured skeptics that sanctions would automatically “snap back” into effect if Iran violated any terms of the nuclear accord. “The UN sanctions that initially brought Iran to the table can and will snap right back into place,” Kerry told reporters in Vienna. That echoed what his boss had been saying all along. “We can crank that dial back up,” Obama told an interviewer in 2013. “We don’t have to trust them.”

Yet now they sell the deal as a last chance to salvage some Iranian compliance from a sanctions regime that is crumbling anyway. (Switch!) Our allies “certainly are not going to agree to enforce existing sanctions for another 5, 10, 15 years,” Obama said in his American University speech last month. And in any case, “sanctions alone are not going to force Iran to completely dismantle all vestiges of its nuclear infrastructure.” Snap back? That was merely bait.

Right to enrich. A deal with Iran absolutely would not invest the Islamic Republic with a right to enrich uranium, the administration firmly asserted. “No — there is no right to enrich,” Kerry declared. “In the Non-Proliferation Treaty (NPT), it’s very, very clear that there is no right to enrich.” This was a key point, since Iran insisted not only that it did have a right to enrich uranium, but that the West must acknowledge that right, or there would be no deal.

Before long, however, Kerry had changed his tune. “The NPT is silent on the issue,” he conceded in testimony before a House committee. The final deal authorizes Iran to operate 6,000 centrifuges and to continue enriching uranium. “We understood that any final deal was going to involve some domestic enrichment capability,” a senior administration official told The Wall Street Journal in April. “We always anticipated that.” (Switch!)

Military option. Over and over and over, Obama proclaimed that he meant to prevent Iran from obtaining a nuclear weapon and that all options — including military attack — were “on the table.” But that assurance has gone down the memory hole. (Switch!) As he lobbied for the nuclear deal that was signed in Vienna, his message was reversed. A military option is not on the table and will not eliminate an Iranian nuclear threat, Obama told Israeli TV. “A military solution will not fix it. Even if the United States participates, it would temporarily slow down an Iranian nuclear program but it will not eliminate it.”

Deal or no deal. But perhaps the most egregious bait-and-switch of all involves the standard by which any accord with a deadly regime like Tehran’s should be assessed. From President Obama on down, administration officials used to affirm constantly that “no deal is better than a bad deal.”

They were right. And the deal they produced is indeed a bad deal. It does not dismantle Iran’s nuclear program, nor constrain its murderous ambitions, nor lessen its influence. It will not enhance the security of America and its allies, nor make the world more peaceful.

Yet the president and his allies have abandoned their old standard. Their case for this bad agreement comes down to: It could be worse. It may be flawed and far from what was promised, but any deal with Iran is better than no deal. Most Americans, and most members of Congress, don’t agree. And the bait-and-switch that was used to clinch this sale is going to leave a bad taste in a lot of mouths for a long time to come.

Jeff Jacoby is a columnist for The Boston Globe.