GREENVILLE, S.C. (AP) — George W. Bush won a bruising South Carolina presidential primary on his way to the Oval Office, as his father did before him.

Now it’s his brother’s turn, and for Jeb Bush, the most consequential foreign policy decisions of his brother’s tenure are suddenly front-and-center in his bid for the Republican presidential nomination — thanks to Donald Trump.

The 43rd president already had announced plans to campaign for his younger brother Monday in South Carolina, marking his most direct entry into the 2016 race to date, when Trump, the GOP front-runner, used the final debate before the state’s Feb. 20 primary as an opportunity to excoriate George W. Bush’s performance as commander in chief.

The former president, Trump said, ignored "the advice of his CIA" and "destabilized the Middle East" by invading Iraq on dubious claims that Saddam Hussein had weapons of mass destruction.

"I want to tell you: They lied," Trump said. "They said there were weapons of mass destruction. … And they knew there were none."

Trump dismissed Jeb Bush’s suggestion that George W. Bush built a "security apparatus to keep us safe" after the 9/11 attacks.

"The World Trade Center came down during your brother’s reign," Trump said, adding: "That’s not keeping us safe."

The onslaught — "blood sport" for  Trump, Jeb said — was the latest example of the billionaire businessman’s penchant for mocking his rival as a weak, privileged instrument of the Republican Party establishment.

But the exchange also highlighted the former Florida governor’s embrace of his family name as he jockeys with Florida Sen. Marco Rubio and Ohio Gov. John Kasich to emerge from South Carolina as the clear challenger to Trump, who won the New Hampshire primary, and Texas Sen. Ted Cruz, the victor in Iowa’s caucuses.

The approach takes away from Bush’s months-long insistence that he’s running as "my own man," but could be a perfect fit for South Carolina. "The Bush name is golden in my state," says South Carolina Sen. Lindsey Graham, who ended his White House run in December and endorsed Jeb Bush in January.

George W. Bush retains wide appeal among Republicans, from evangelicals and business leaders to military veterans. All are prominent in South Carolina, with Bush campaign aide Brett Doster going so far as to say that George W. Bush is "the most popular Republican alive."

After the debate, some Republicans again suggested Trump had gone too far. Bush wasn’t alone on stage leaping to his brother’s defense, with Rubio coming back to the moment to say, "I thank God all the time it was George W. Bush in the White House on 9/11 and not Al Gore."

The attack on George W. Bush carries risk for Trump, given the Bush family’s long social and political ties in South Carolina and the state’s hawkish national security bent, bolstered by more than a half-dozen military installations and a sizable population of veterans who choose to retire in the state.

Bush and his backers certainly hope it’s the case. Right to Rise USA, a super political action committee backing Bush, is airing two television ads blasting Trump and touting Bush for taking him on, and on Friday, a committee spokesman says, a radio ad will launch that compiles multiple audio clips of Trump using profanity in public settings, most recently when he used an uncouth epithet about Cruz.

"The time is now for South Carolina to end the Trump charade," an announcer says.

Yet Trump has repeatedly defied predictions that his comments might threaten his perch atop the field.

As he jousted Saturday with Trump, Jeb Bush said, "this is not about my family or his family."

But the Bushes have quite a history in South Carolina. In 2000, George W. Bush beat John McCain in a nasty contest, marred by rumors that McCain had an illegitimate black child. McCain adopted a child from Bangladesh. George H.W. Bush, the 41st president, won twice here, beating Bob Dole in 1988 and demolishing Pat Buchanan in 1992.

One of the elder Bush’s top strategists, Lee Atwater, hailed from South Carolina. Last week, Jeb Bush touted the endorsement of Iris Campbell, the widow of former South Carolina Gov. Carroll Campbell, a national co-chairman of previous Bush presidential campaigns.

Yet even as he defended his brother’s presidency at Saturday’s debate, Jeb Bush found a way to distance himself from George W. Bush’s business affairs — and criticized Trump at the same time. The issue: eminent domain.

Before entering politics, George W. Bush was part-owner of the Texas Rangers, and their home city of Arlington, Texas, used eminent domain to take private land and build a stadium for the team. Trump has defended such uses of eminent domain as a way to foster economic development.

Retorted Bush, who argued eminent domain should be reserved for public infrastructure projects, "There is all sorts of intrigue about where I disagree with my brother. There would be one right there."

Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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