President Obama addresses the nation from the Oval Office on Sunday. (Jacquelyn Martin/AP)

President Obama had made nine public statements after the Nov. 13 attacks in Paris, but late Friday afternoon, after the shootings in San Bernardino, Calif., he decided that would not be enough.

So he instructed his team to begin preparing for a national address that he would deliver Sunday night — remarks he would tinker with even after he ushered several entertainment luminaries out of the East Room and on their way to the Kennedy Center, 21/hours before he began speaking on live television.

Two recent attacks connected to the Islamic State — one in Paris last month and a mass shooting in San Bernardino less than a week ago — have put the country on edge and the administration on the defensive. The president has been forced to reevaluate, or at least reassert, his approach to conflict in the Middle East that many Americans now see as an immediate threat to their own security.

Even as the president reassured Americans that he remains committed to pursuing the strategy for the Middle East that he outlined more than a year ago, White House officials are quietly reexamining how to intensify the campaign against an elusive foe that has inspired homegrown terrorism in the United States. But the changes under consideration do not stray beyond a set of limited options, with the president reiterating his opposition to a large-scale ground force, which he said would only help the Islamic State recruit new foot soldiers.

“The administration is open to new ideas and new approaches and considering some old approaches it had rejected in the past,” said Rep. Adam B. Schiff (Calif.), the top Democrat on the House Intelligence Committee. “That is not always an impression one gets from the public statements.”

President Obama’s address comes as recent attacks in Paris and California have raised concerns about terrorist threats. (Saul Loeb/AP)

Even before the San Bernardino attacks, Americans took a dim view of Obama’s performance on terrorism. In a Washington Post-ABC News poll conducted after the Paris attacks but before the California shootings, a record-low 40 percent of Americans approved of his handling of threats of terrorism, far from its peak of 69 percent after Osama bin Laden was killed in 2011. Only 35 percent approved of his handling of the Islamic State in the poll.

On Monday, Michael McCaul (R-Tex.), chairman of the House Homeland Security Committee, said in a speech at the National Defense University that Obama’s “leadership void has put the United States homeland in the highest threat environment since 9/11.”

“For far too long, we have allowed extremists to reclaim their momentum, surging from terrorist cells into full-fledged terrorist armies,” he said. “As a result, I believe the state of our homeland is increasingly not secure, and I believe 2015 will be seen as a watershed year in this long war — the year when our enemies gained an upper hand and when the spread of terror once again awoke the West.”

White House officials said Monday that the president and his team have worked to adapt to the changing fight against the Islamic State, also known as ISIL or ISIS. At the same time, they are counseling patience to a nation not known for such an inclination.

“When the president first ordered military action against ISIL targets in Iraq and in Syria more than a year ago, he acknowledged that this would be a process that would take some time, principally because the president was not going to commit U.S. ground troops to a sustained ground combat operation inside of Iraq and in Syria,” White House press secretary Josh Earnest said Monday.

Earnest also said “this is one of the lessons that we, hopefully, have learned from our recent history: that our victory . . . will be more long-lasting and enduring if we pursue the strategy that the president has outlined, which is building up the capacity of local security forces to fight for their own country.”

The president’s policy toward the Islamic State goes deeper than questions of tactics. Obama is grappling with a fundamental disconnect between his vision of Islamist extremism, which he sees as a significant but not existential threat, and the darker, more sweeping view espoused by leading Republicans and shared by many Americans.

“Do we believe a few bombings, whether it’s in Paris or California or Texas is going to bring down the country? I do not,” said former congressman Lee H. Hamilton, an Indiana Democrat who now directs the Center on Congress at Indiana University and received the Presidential Medal of Freedom last month. “Managing the relationship with China . . . is much more important for the long-term security of the country. That does not say it’s not a serious threat, however. So it’s a hard thing to get across.”

In the past few days, Obama has worked to signal how gravely he takes Americans’ safety. He and his advisers chose the Oval Office as the setting, a top aide said, because it “conveys the seriousness with which we are taking the issue.” On Monday, the president attended a meeting with his national security adviser Susan E. Rice, the U.N. ambassadors of the 15 Security Council members and the ambassadors of the five countries who will begin their terms on the council in January.

“He wants people to know he gets it,” said Philip H. Gordon, former National Security Council director for Middle East policy and now a fellow at the Council on Foreign Relations. “He wants to underscore that he wakes up every single day and focuses on this issue.”

At the same time, Gordon said, “one of the reasons the president has not delivered the Churchillian call to arms after the attacks in Paris or California that some of his critics want is because that implies a Churchillian response.” And that isn’t what the president, or most of his critics, want.

“The president is very attuned to unintended consequences,” Gordon said.

All the same, U.S. involvement has deepened slowly, noted Richard Fontaine, president of the Center for a New American Security. He said the administration has gone from dropping humanitarian aid for Yazidis in Iraq to bombing targets in Iraq and Syria, from pledging not to put soldiers on the ground in Iraq to having more than 3,000 there and Special Operations troops due in Syria.

Amid this, Obama has renewed his push for explicit congressional authorization in the battle against the Islamic State, saying, “If Congress believes, as I do, that we are at war with ISIL, it should go ahead and vote to authorize the continued use of military force against these terrorists.”

Sen. Timothy M. Kaine (D-Va.), who has pressed repeatedly for a new authorization for use of military force (AUMF), said in an interview that he is convinced that “Congress is going to finally be dragged into this, not because of anything the president has said or because I’ve persuaded someone to change their vote, but because the threat of ISIL will become more and more apparent to the American public, and it will be harder and harder for Congress to hide.”

Still, even that initiative might be difficult to pass in a Congress controlled by Republicans who question the administration’s proposal and who suggest that Obama bears much of the blame for the current threat level.

Sen. John Cornyn (R-Tex.) said in an interview that Obama’s decision to withdraw troops from Iraq contributed to the rise of extremism there: “The president is kind of like the doctor who’s not treating the root disease and is just managing the symptoms.”

Cornyn said he was “skeptical” that an authorization of force against the Islamic State would win enough support. “It seems like the Democrats’ interest in the AUMF is in putting limitations on how future presidents could combat terrorism,” he said.

Beyond that renewed push, it is unclear how much the White House will pursue a different course. Schiff said the administration is looking again at creating a safe buffer zone in Syria, but such a move will require delicate negotiations with the Turkish government; White House officials, though, have suggested that there is no plan to establish such a zone. For now, Obama is pressing Turkey to secure a substantial piece of its border through which Syrians now move relatively easily.

Although Americans may want a more emotional display from the president, Hamilton said there are limits to what they will see from Obama. “He’s just not a passionate leader, that’s all,” he said. “He’s an intellectual man.”

Scott Clement contributed to this report.