The former Florida governor has routinely accused the Obama administration of tearing down the military through budget cuts that he says have weakened the country's standing in the global balance of power.
And he continued that criticism of the President and Hillary Clinton in a speech at The Citadel military college in Charleston, South Carolina, where Bush offered a four-pronged plan to build up the military, and, as he sees it, take back the mantle as the world's leader, with the Paris attacks as a backdrop.
"Radical Islamic terrorists have declared war on the western world. Their aim is our total destruction. We can't withdraw from this threat, nor negotiate with it," Bush said. "We have but one choice: to defeat it."
While the speech was scheduled before the terrorist attacks in France, Bush is seizing the moment as well as on scrutiny over Obama's ISIS strategy to brand himself as the tried and trusted leader -- the safer option for a Republican primary electorate that has so far preferred candidates with no political experience according to polling.
"The United States should not delay in leading a global coalition to take out ISIS with overwhelming force," Bush said.
He called for the United States to intensify both its air and ground efforts against the group in Syria and Iraq, and raised the prospect of a land war in the Middle East.
"The United States -- in conjunction with our NATO allies and more Arab partners -- will need to increase our presence on the ground," Bush said.
Bush appeared on five morning news shows on Sunday and Monday, calling for the U.S. to "declare war" against ISIS and urged the use of "massive force" to take out the terror group.
As he did Tuesday during a three-stop tour across South Carolina, Bush argued Wednesday that the presidential race has taken on a more somber, realistic tone.
"This brutal savagery is a reminder of what is at stake in this election. We are choosing the leader of the free world," he said. "And if these attacks remind us of anything, it is that we are living in serious times that require serious leadership."
In a call with business leaders later Tuesday, Bush offered loaded criticism of Obama for saying last week that ISIS had been contained and for allowing the expansion of the terror group's reach to expand on his watch.
"In effect, this President wants to run out the clock and leave this responsibility to the next president," Bush said.
Bush's hawkish rhetoric about ISIS garnered him thunderous applause Tuesday night at a town hall in Conway, a small city not far from the Grand Strand coast.
"Every day they exist, they create instability that we're going to have to deal with either here or there. Which one do you want? I believe we should take it to them there and do it in a comprehensive way where we lead the world."
Laying out a plan
The presidential candidate has repeatedly reminded voters this week that he laid out a plan this summer to take on ISIS
, and he did so again in his speech.
While the proposal mirrored some actions already taken by the Obama administration, Bush differed from Obama in calling for a no-fly zone in Syria and for embedding troops with the Iraqi military.
More broadly, Bush called Wednesday for increasing the size of the U.S. Army by 40,000 soldiers and the size of the Marine Corps by 4,000 Marines. He's also in favor of increasing the size of the Navy and boost Virginia class submarine production, according to his campaign.
To push back against Russia, Bush would increase commitment to NATO, including sending an Army Special Forces Group back to European Command, he said. He would also favor more joint military exercises with other countries.
The Pentagon, he argued, is bloated with waste, and he said he plans to reduce the number of Washington bureaucrats to free up resources for more uniformed military.
As for homeland security, he placed emphasis on securing the borders, improving cybersecurity and protecting infrastructure.
'You can prove you're a Christian'
Bush also faced questions earlier this week about the refugee crisis in Syria.
While he has previously taken a more compassionate tone than other candidates on taking in Syrian refugees -- he boasts among his supporters a Syrian-American woman who has appeared at several of his events -- Bush has taken a more hardline stance since the Paris attacks, saying he would prioritize Christian refugees.
Speaking to reporters at a barbecue joint in Florence, South Carolina, he said the United States should take in "people like orphans and people who are clearly not going to be terrorists. Or Christians."
Even then, he supports House Speaker Paul Ryan's suggestion to take a "pause" on accepting refugees until proper screening and vetting procedures are in place to prevent members of ISIS from taking advantage of asylum grants.
Asked whether he would bar moderate Muslims entirely, Bush said he wants to see what the vetting process looks like first.
He was also asked how he would distinguish between Muslims and Christians.
"You can prove you're a Christian," he said. Pressed further on how, Bush shrugged his shoulders and replied: "I think you can prove it. If you can't prove it, then, you know, you err on the side of caution. "
Bush also pushed back on Obama's criticism Monday
of candidates who issued a preference for Christian refugees over Muslim ones. Speaking in Conway, Bush said the persecution of Christians in the Middle East "should haunt us as a nation."
"The President got after me indirectly on this yesterday, saying that somehow it was wrong to say what I just said and not have the same sympathies for Muslims. Well I do. We all have sympathies for people that have been uprooted," he said, but added: "Look, we have a duty to protect our country as well."
'Elections are about the future, not the past'
The unrest in the Middle East has been a quagmire this year for Bush's campaign because of his brother's involvement in the region with the war on terror. While Bush danced around how to handle questions about his brother and specifically Iraq earlier this summer, he seemed to find his footing when he started focusing on a message that George W. Bush kept the country safe after the 9/11 attacks.
Jeb Bush won accolades from Republican voters when he defended his brother in the second Republican presidential debate against Donald Trump, and again in October when Trump criticized George W. Bush for 9/11 attacks happening on his watch.
And though Jeb Bush is attempting to craft his own brand, it's clear that he sees some advantages in building on his family history.
Bush embraced the legacy of his father, former President George H.W. Bush, and his handling of the Gulf War, for example, on Tuesday. At the barbecue joint, the younger Bush recalled the war as "one of the most effective victories, where we had a strategy, we act(ed) on a strategy, we won and we left."
And while one woman in Florence told him, "I loved your brother, George," and encouraged Jeb Bush not to "get that much further away from him like some people suggest," another woman in Conway took a more confrontational tone, reminding Bush that his brother created the most debt of any U.S. president, second only to Obama.
Asked by a separate voter in Conway how he can convince the country that it needs a third Bush presidency, Bush said he loved his family but that "elections are about the future, not the past."
He pledged to run on the merit of his own record, arguing that it could easily outmatch Hillary Clinton in a general election.
"We can win. That's how I'll win," he said. "And I'll do it proud of my brother and proud of my dad."