Donald Trump and former Florida governor Jeb Bush are trading insults on the campaign trail. Here’s a few of their best sparring moments. (Pamela Kirkland/The Washington Post)

Jeb Bush went on the offensive Tuesday against GOP presidential front-runner and frequent antagonist Donald Trump, releasing an attack video portraying the mogul as a closet liberal and signaling that he will attempt to bring Trump down in coming weeks.

“He attacks me every day. He attacks me every day with barbarities,” Bush said in Spanish in response to questions from reporters at a Presbyterian school here. “They’re not true. What we did today was to put out in his words to show that he’s not conservative.”

But in fully embracing a fight against Trump, Bush is embarking on a risky strategy that could further fuel Trump’s unexpected rise and complicate his own path to the nomination. Allies of the former Florida governor insist that he had no choice but to adopt a more aggressive posture, elevating his feud with Trump to the marquee contest in the GOP primary contest.

Republicans said the dilemma for Bush is obvious. If he hangs back, voters may conclude he is weak. If he attacks, he engages a candidate who has proved to be an effective counterpuncher. For now, the conclusion in the Bush campaign is that appearing weak is the greater risk.

“Knowing Jeb, I’m sure he’d prefer to be talking about policy proposals rather than trading verbal jabs with Trump,” said Ana Navarro, a longtime GOP strategist backing Bush. “But what . . . is he going do? Let the guy mischaracterize his record and positions and attack him daily? Enough is enough. If Trump wants to pick a fight with Jeb, Jeb needs to embrace it and hit back.”

Republican presidential candidates Donald Trump, left, and Jeb Bush participate in the first Republican presidential debate Aug. 6. Bush has ratcheted up his attacks on Trump, who is ahead in most polls. (Andrew Harnik/Associated Press)

Bush’s release of the Web video — amplified by his sharp attacks in English and Spanish after a town hall meeting here — marked a departure from weeks of reluctant, mostly tepid criticism of Trump, who has routinely assailed Bush for not having the “energy” to be president, among other taunts. The escalation came after Trump released an aggressive video Monday that flashed mug shots of men charged with or convicted of murder as Bush’s comments that undocumented immigrants enter the United States as “an act of love” played in the background.

The video Bush released Tuesday strings together clips from past interviews of Trump praising Democratic front-runner Hillary Rodham Clinton and voicing support for abortion rights, tax increases for wealthy Americans and the 2009 economic stimulus program.

In the remarks he delivered in Spanish in Miami, Bush’s tone and word choices were sharper than what he has said on the topic in English.

Some Republicans are skeptical that Bush’s issue-based strikes will undercut Trump’s appeal, which is based less on ideology than on broad anger about the direction of the nation.

“We have reached a moment where conservatism isn’t defined by issues anymore for a big percentage of the country,” said Steve Schmidt, a senior adviser to Sen. John McCain (R-Ariz.) in the 2008 presidential campaign.

Bush faces other perils as well. One is that his attacks will overshadow the positive elements of his message. They also could strengthen Trump by heaping even more attention on his campaign, which has thrived under the spotlight. A new Loras College poll of likely Iowa Republican caucusgoers released Tuesday showed Trump leading the pack, with 25 percent support. Bush lagged behind at 10 percent and has finished even lower in other recent surveys.

“Yet another weak hit by a candidate with a failing campaign,” Trump tweeted Tuesday. “Will Jeb sink as low in the polls as the others who have gone after me?” Trump also released an Instagram video that sought to link the Bushes to the Clintons.

Other candidates are letting Bush and Trump squabble while continuing to try to build support for their campaigns in traditional ways. For some, the absence of attention is considered beneficial right now, as none of the others want to get into a public fight with Trump.

“We’ve gotten out our popcorn. It’s wonderful,” said a strategist for a rival campaign, who spoke on the condition of anonymity to discuss the matter frankly. “I don’t think it’ll work.”

Although Bush remains the GOP establishment favorite, Ohio Gov. John Kasich, Sen. Marco Rubio (Fla.) and Wisconsin Gov. Scott Walker could emerge as alternatives if Bush struggles. Kasich is rising in the polls in New Hampshire, Walker is seeking a campaign reboot and Rubio has stuck to casting himself as a new-generation candidate while mostly avoiding the fights that have consumed Trump and Bush.

“I think there is some wisdom to staying out of the fray between these two individuals and letting them hammer it out,” said Frank VanderSloot, a top Republican donor whose three favorite candidates are Rubio, Walker and Bush. But he added: “At some point they are going to have to come up and take a stand against” Trump’s positions.

Bush’s focus on Trump is partly a response to donors who have been clamoring for a more aggressive posture. Once Bush began his first, hesitant criticism of Trump two weeks ago in New Hampshire, several surrogates and donors suggested it was long overdue.

On Tuesday, Bush also batted away suggestions that he’s struggling to raise money, noting that he attended seven fundraisers last week and another on Monday night in Coral Gables, Fla.

In past campaigns, establishment-favored contenders have successfully attacked upstart opponents. In 2012, former Massachusetts governor Mitt Romney went hard after former House speaker Newt Gingrich (Ga.) en route to the Republican nomination.

But Bush, running against a deep and well-funded field, has not received the level of support that Romney had. Romney also never had to contend with a rival quite like Trump, who has upended conventional thinking about modern campaigns.

“Trump is completely, absolutely and utterly in command of the political battle space,” Schmidt said. “He is controlling the entire tone and tenor of the campaign.”

Sullivan reported from Washington. Dan Balz and Robert Costa in Washington contributed to this report.