Exactly one year ago, President Obama was weighing whether or not to take military action in Syria. On Sept. 10, 2013, he addressed the nation to make the case for his strategy, citing national security concerns. But the public was skeptical. So was Congress.

This Sept. 10, Obama is again planning to make a televised case to the nation for action in Syria. Once more, he's going to lay out a broad strategy, in remarks that are again likely to focus on the potential threat to American lives and interests.

It's all oddly familiar. And completely different.

Last year, the president sought authorization from a Congress that eventually seemed unlikely to grant it. Now he appears unlikely to seek their formal approval. But far more of them, on both sides of the aisle, seem to have already bought in to his arguments this time around -- or appear hungrier for an even more aggressive strategy than he's likely to lay out Wednesday.

Last year, Obama faced a war-weary public deeply unhappy with the prospect of a fresh Middle East intervention. Today, he's seeing a renewed appetite for action. According to a new Washington Post poll, 65 percent of the public support expanding airstrikes against Iraqi insurgents into Syria -- almost a complete reversal of the results of the Washington Post-ABC News survey around this time last year, when 61 percent of respondents said they opposed the United States launching missile strikes against the Syrian regime.

The sea change in public and political reaction is rooted in -- though not entirely explained by -- the sharply different circumstances.

This time, the president isn't looking to strike a state, or effectively take sides in a civil war, or move against individuals who haven't directly attacked U.S. interests. He isn't acting on evidence that's ever been in any significant dispute.

He won't need to repeat his plea of a year ago, for "every member of Congress, and those of you watching at home tonight, to view those videos of the [chemical weapons] attack" in Syria. This time, he's taking aim at a group of Islamic militants who have already killed Americans in horrific, verified footage that's been widely viewed.

On "Meet the Press" this past weekend, Obama stressed that the Islamic State poses no known immediate threat to the United States -- but cast the current U.S. action against the group, and any potential future moves, as a fight against terrorism. "I'm preparing the country to make sure that we deal with a threat from ISIL," Obama said on "Meet the Press." "Keep in mind that this is something that we know how to do. We've been dealing with terrorist threats for quite some time."

"The situation a year later is markedly different," White House Press Secretary Josh Earnest said. "What we’re talking about now is confronting a terrorist group that has sought a safe haven in Syria. This is a group that poses a threat to Americans in the region and could potentially, down the line, pose a broader threat to American interests and our allies around the globe. So the situations are somewhat different."

Even though he may not ask for formal congressional authorization this time around, Obama is still looking for their support. The president will meet with Hill leaders Tuesday to discuss his strategy against the Islamic State. National Security officials are expected to brief senators Wednesday and House members Thursday.

"I'm confident that I have the authorization that I need to protect the American people," Obama said on "Meet the Press" Sunday. "And I'm always going to do what's necessary to protect the American people. But I do think it's important for Congress to understand what the plan is, to have buy-in, to debate it."

On Capitol Hill, there are some, such as Sen. Tim Kaine (D-Va.), who say this isn't enough -- that authorization isn't an optional step. And there are voices who have raised concerns about the risks of expanded military action. But the dominant mood is far more supportive of a military response than it was last year.

This time around, isolationists are turning hawkish, and hawks are sharpening their talons.

"We must expand our bombing campaign to include ISIS bases in Syria," Sen. Dan Coats (R-Ind.) said in a statement, referring to an acronym used to describe the Islamic State. 

In an op-ed for Time titled, "I am not an isolationist," Sen. Rand Paul (R Ky.) wrote, "Some pundits are surprised that I support destroying the Islamic State in Iraq and Greater Syria (ISIS) militarily.

"If I had been in President Obama's shoes, I would have acted more decisively and strongly against ISIS. I would have called Congress back into session -- even during recess," Paul wrote.

Two Republican senators said Monday that they believe U.S. Special Forces should be sent into Syria and Iraq to combat the Islamic State -- going further than the president himself, who has consistently said that he will not send ground forces in to Iraq or Syria.

Action against the Islamic State has even become a campaign issue. Republican White House contenders have called on President Obama to take even tougher action against Islamic State militants than the current rounds of airstrikes in Iraq. And in this midterm election year, candidates have made similar critiques.

"ISIS makes al-Qaeda look like Boy Scouts," former Massachusetts Senator Scott Brown (R), now running for Senate in New Hampshire, said. He put the clip into a campaign video. "We have one of the most inconsistent foreign policies right now."

The international environment has also shifted sharply. Last year, British Prime Minister David Cameron suffered a stinging defeat when the House of Commons defeated his proposal to take military action in Syria.

Public opinion seems to have shifted in the United Kingdom as well. According to a YouGov/Sunday Times poll conducted in late August, 45 percent of respondents support British air strikes against the Islamic State.

Obama made the case for a broad international and regional strategy to fight against the Islamic State at the NATO summit in Wales last week to European countries increasingly worried about the threat of foreign fighters who hold Western passports. The alliance formed a 10-nation coalition that could reach out to Syrian rebels as proxy fighters in the battle against the Islamic State -- and the president will convene a meeting of the United Nations security council this fall to discuss the foreign fighter issue.

"There’s great conviction that we have to act as part of the international community to degrade and ultimately destroy ISIL," Obama said in Newport, Wales, last week. On Wednesday, he'll tell Americans what that effort might look like.