Democrats are joining Republican presidential front-runner Donald Trump’s attacks suggesting that George W. Bush didn’t do enough to stop 9/11.

Trump and opponent Jeb Bush have been openly warring over the former president’s legacy. Trump took it up a notch over the weekend, arguing that because the Sept. 11, 2001, terrorist attacks took place under George W. Bush’s watch, he is partly responsible for not having stopped them.

Liberals, once hesitant to make the same leap, have picked up on the line with aplomb.

On Monday, former Democratic National Committee communications director Brad Woodhouse sent an email to supporters with the subject line “Trump is right about 9/11,” linking to an article with the same headline in The Atlantic that argues George W. Bush could have done more to prevent the attack.

Meanwhile, liberals trumpeted an exchange between Jeb Bush and CNN anchor Jake Tapper from over the weekend in which the former Florida governor had to answer why his brother shouldn’t shoulder more blame for the nation’s security leading up to 9/11 if Republicans can blame former Secretary of State Hillary Clinton for the lack of security leading up to the 2012 terrorist attack on the U.S. diplomatic compound in Benghazi, Libya.

By fanning the fire from Trump, Democrats are looking to pile on Jeb Bush, a presidential contender the party has long seen as a formidable general election candidate but who has struggled to maintain his standing in the Republican primary.

“Democrats are happy to undermine Jeb in any way here, and this really is a twofer,” said Democratic strategist Brad Bannon. “It’s an attack on someone who is not doing well in the primary but who could run strong in the general election. And it raises the specter of the [George W.] Bush years, which many voters still remember in a negative light.”

The debate around whether the 43rd president did enough to keep America safe in the run-up to the 9/11 terror attacks resurfaced at the last Republican debate, when Trump claimed that George W. Bush’s administration was such a “disaster” that it paved the way for Barack Obama to become president.

On the debate stage that night, Jeb Bush effectively ended the argument among his Republican colleagues by declaring that, “as it relates to my brother, there’s one thing I know for sure — he kept us safe.”

However, the progressive group Americans United for Change, led by Woodhouse, quickly cut the White House contender’s remarks into an ad that batters him for seeking to “rewrite history.”

Trump is now diving into a ¬relitigation of the George W. Bush years, hoping to keep his 2016 foe on the defensive.

Democrats, meanwhile, believe they continue to benefit from Trump’s no-holds-barred style in going after Republicans and are gleeful that the outspoken billionaire has broached the issue.

“We are very much open to Republicans duking it out over the legacy of George W. Bush’s administration,” said Preston Maddock, a spokesman for the liberal super-PAC American Bridge. “No one has left the White House with a lower approval rating than him, so this is favorable ground for us.”

While many Democrats are increasingly taking Trump more seriously as a potential general election candidate, they’re also confident they could defeat him in 2016, believing his remarks on women and immigrants, among other things, would ultimately sink him.

In Jeb Bush, many in the party see a wounded former front-runner ripe for a knockout and someone who is on his heels when discussing his family’s legacy.

Earlier in the cycle, Jeb Bush struggled for days to answer the question of whether he would have invaded Iraq knowing what he knows today.

“One of the biggest questions Jeb Bush faces is how to deal with his last name, and his brother in particular, so every day that he’s dealing with this is a lost day for him in his quest for the Republican nomination,” said Democratic strategist Joe Trippi.

The Republican National Committee has once again been dragged into a fight involving the real estate tycoon’s preferred lines of attack.

“We believe it’s much more helpful, much more beneficial in the long run, if we’re actually focusing on why we’re better and why our candidates are better,” RNC spokesman Sean Spicer said on CNN over the weekend.

And Trump has drawn the ire of several prominent Republicans, including Rep. Pete King (R-N.Y.) and GOP presidential candidate Ben Carson, as well as notable Bush administration officials, who have long since tired of his attacks against the field and are now chastising him for seeking to draw divisions within the party where none previously existed.

“This is extreme poor taste,” said Dov Zakheim, an undersecretary of Defense in George W. Bush’s administration. “He’s handed liberals another club to beat George Bush with, not that they ever cared what club they were using. The British, Russians and Spanish have all had terror attacks since 9/11. We haven’t had any, and that’s because of President Bush, who laid the groundwork for Obama to be able to say the same thing.”

Jeb Bush is seeking to use the dispute to his advantage. He’s been more sure-footed and aggressive in taking on Trump over the remarks, calling the businessman “pathetic,” questioning his foreign policy bona fides and temperament to lead the country and even seeking to galvanize his supporters by fundraising off the remarks.

“One has to wonder about Trump’s loyalties,” said Zakheim. “He’s given to the Democrats in the past and he’s doing it again.” 

Democrats are happy to accept the gift and plan to use it to keep the heat on Jeb Bush.
 “This is smart politics for Trump, because it puts Jeb in a position where he has two options, both bad,” said Maddock. “One, he doesn’t defend his brother and comes off as weak. Or two, he defends himself, in which case he doesn’t have the facts on his side.”