Former President George W. Bush’s absence from this year’s Republican National Convention is a problem. It’s a problem not merely because it signifies GOP opposition to Donald Trump. More importantly, it’s a problem because it underscores the Trump campaign’s inability to define the word “again.”

“Again” is a big word this week in Cleveland. Monday’s convention theme was “Make America Safe Again.” Tuesday’s is “Make America Work Again.” Wednesday’s is “Make America First Again.” Thursday’s is “Make America One Again.” The convention itself, of course, is titled “Make America Great Again.”

For conservatives, these phrases evoke a bygone era—either the 1950s or 1980s—when America had more manufacturing jobs, less terrorism, fewer Mexicans and Muslims, and more docile blacks. But conventions are not just exercises in cultural nostalgia. They’re advertisements for a political party. Which is why speaker after speaker on Monday night sought, awkwardly, to suggest that America went to hell under Barack Obama without ever mentioning what things were like under the Republican who preceded him.

Alabama Senator Jeff Sessions bemoaned the fact that “the incomes of middle-class Americans today are $4,186 per year less than in 1999.” That’s true. But most of that decline occurred before Obama took office. By trying to ignore George W. Bush, Sessions essentially suggested that making “America Great Again” means a return to 1999 and putting the Clintons back in charge.

Other speakers were vaguer. “The world,” declared Retired Lieutenant General Michael Flynn, “has lost faith in American leadership.” House Homeland Security Committee Chairman Michael McCaul declared, “Our allies no longer trust us.”

So when did they trust us? If Flynn and McCaul are suggesting that other countries had more faith in American leadership in 1946, or even 1996, than they do in 2016, they may be right. But if they’re comparing perceptions in 2016 with, say, perceptions in 2006, they’d be dead wrong. In fact, America is far more trusted overseas than it was when a Republican last held the White House. According to the Pew Research Center, “Confidence in the U.S. president to do the right thing regarding world affairs” stood at roughly 20 percent in Britain, Germany, France, and Spain during George W. Bush’s last year in office. By this June, that figure among those four key U.S. allies ranged between 75 percent and 86 percent. America is significantly more popular outside of Western Europe, too. Between the final years of the George W. Bush presidency (Pew polled some countries in 2007, others in 2008) and the final years of the Obama presidency (2015 or 2016), America’s favorability rating rose 9 points in China; 10 points in Canada; 14 points in Australia, South Africa, and South Korea; 19 points in Mexico; 21 points in Argentina; 22 points in Japan; 25 points in Indonesia; 27 points in Malaysia; and 32 points in Tanzania. Only in the Middle East has America’s image remained roughly the same. Currently, it seems the world does have faith in American leadership.

The most creative answer to the Bush problem came from Rudy Giuliani, who defined the prelapsarian Republican era to which America must now return not as Bush’s presidency of the United States but as his mayoralty of New York. “It’s time to make America safe again. It’s time to make America one again,” Giuliani declared. “I know it can be done, because I did it by changing New York City …What I did for New York City, Donald Trump will do for America.” It’s certainly true that between 1994 and 2001, when Giuliani was mayor, New York grew far safer. But the country as a whole grew far safer, too. In other words, a president has already done for America what Giuliani did for New York. His last name is Clinton.

Giuliani’s argument underscores how much easier Hillary Clinton’s revivalist argument is than Trump’s. Next week in Philadelphia, if she talks about restoring good times, she can mention the years in which she lived in the White House. On Monday in Cleveland, when Republicans talked about restoring good times, they implicitly referred to the same era.

To be sure, Trump isn’t the first Republican presidential nominee to try to evade the Bush legacy. In 2008 and 2012, George W. Bush only appeared at his party’s conventions by video. But although John McCain and Mitt Romney kept their distance from Bush, they still defended his handling of Iraq and the War on Terror. Bush’s secretary of state, Condoleezza Rice, gave a high-profile speech at the GOP convention in 2012. And Romney himself defended Bush’s decision to overthrow Saddam Hussein while repeatedly slamming Obama for withdrawing troops from Iraq, thus undoing the victory that Bush had supposedly engineered via the surge. For Romney, therefore, making America “safe again” actually did mean returning to the era of Bush.

But by slamming Bush for having allowed 9/11 and for invading Iraq, Trump has made it impossible for speakers at this year’s convention to evoke nostalgia for the Bush era. The implicit message of Trump’s convention is that it’s not just Obama who has failed America; Republican leaders have, too. It’s a message with which many Americans agree. It just doesn’t explain why the answer is electing Trump.