In a major address in swing-state Ohio, Trump sought to recreate the strongman persona that powered his political rise. The Republican nominee, reeling from self-inflicted wounds that played into his rival Hillary Clinton's charge that he lacks the temperament to be commander in chief, promised an all-encompassing struggle with Islamic terror modeled on the Cold War.
He demanded tough values tests for would-be immigrants to the United States and pledged to come down hard on American Muslims suspected of radicalism. He vowed to keep Guantanamo Bay open, to join Russia to battle terrorism in the Middle East and to launch a "commission" on radical Islam.
"The time is overdue to develop a new screening test for the threats we face today. I call it extreme vetting. I call it extreme, extreme vetting," Trump declared in laying out the new values-test proposal.
The most important audience for those policies, however, was not in Cairo or Damascus. It was US voters themselves as he sought right his campaign after an erratic performance that has sent him tumbling in the polls.
Having boasted last year that his approval ratings spiked after terror attacks, Trump sought on Monday to harness and intensify a climate of fear and vengeance, and then pin its causes on the current president and his former secretary of state.
He traced a trail of terrorist carnage across Europe -- from Paris and Nice to Brussels and Germany -- that he tied in with attacks on US soil including in Fort Hood, Boston, Chattanooga, San Bernardino and Orlando.
"The rise of ISIS is the direct result of policy decisions made by President Obama and Secretary of State Clinton," Trump said.
"The decisions made by the Obama/Clinton group have been absolutely disastrous," he continued, bemoaning a Libya in "ruins," a "disastrous" civil war in Syria and terrorism in Egypt's Sinai Peninsula.
Trump is facing an urgent need to counter a Clinton campaign charge that could pose an existential threat to his campaign -- the idea that he lacks the knowledge and gravitas to be commander-in-chief -- and to quell panic among Republicans who fear he is driving their ticket into the ground.
As soon as he finished his remarks, Trump's critics pointed to falsehoods, contradictions and doubts that his approach would have any meaningful impact on the bloody maelstrom in the Middle East. But the real estate mogul is banking on his hawkish stance striking a nerve with a scared public looking for strong leadership.
To that end, he built out his plan to temporarily suspend Muslim immigration and to extend that prohibition to anyone from nations where terrorism has taken root.
Trump also called for a beefed up approach on homeland security.
"The support networks for radical Islam in this country will be stripped out and removed one by one, viciously if necessary. Viciously if necessary," he pledged.
And he lambasted Clinton with the same criticism she's leveled at him in trying to make the case that his are the safest hands to steer the country.
"Incident after incident proves again and again Hillary Clinton lacks the judgment ... stability and temperament and the moral character to lead our nation," he charged. "She also lacks the mental and physical stamina to take on ISIS and all of the many adversaries we face."
The question now for Trump is whether his teleprompter-based assault, which lacked the spontaneity of his earlier stump speeches, can succeed after the serial setbacks of recent weeks.
It may be that his controversial statements over the past month -- including an apparent call for Russia to hack US servers to find Clinton's missing emails, his musings about whether Second Amendment activists could stop her Supreme Court nominees if she were president or claims that Obama "founded" ISIS -- have inflicted too much damage already for his message to resonate.
With less than three months until the election and with battleground state polls showing Trump heading for defeat, even the billionaire has publicly mused that he could lose. But the Democrats certainly don't want to give him any opportunity to recover.
Vice President Joe Biden on Monday hammered away at the GOP nominee.
Campaigning with Clinton in Pennsylvania, Biden pointed to the military officer who follows him around with a briefcase containing nuclear codes.
"(Trump) is not qualified to know the codes," Biden claimed.
Even some critics within his own party jumped on Trump's speech Monday.
Michael Steel, former adviser to former House Speaker John Boehner, questioned Trump's approach on immigration.
"It was a series of slogans without any policy behind it. He favors 'extreme vetting' -- as far as I know that is a skateboarding term," Steel told CNN's Jake Tapper.
Many national security experts were also not impressed.
Retired Lt. Gen. Mark Hertling, a CNN analyst, said Trump's stance on Muslims recalled US internment of Japanese Americans in World War II.
"That kind of talk just scares me," Hertling said.
But Ed Brookover, a former Trump senior adviser, countered that Monday's speech was the latest step in a steady effort by the Republican nominee to lay out a new national security blueprint for America.
"Mr. Trump has been building his case slowly and surely through the campaign," Brookover told CNN's Brooke Baldwin. "He has been, from day one, outlining different proposals he has had to make America safe, to make us more secure and to avoid this existential threat ISIS (is) posing for us."