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By MICHAEL FALCONE ( @michaelpfalcone )

NOTABLES

• THE LATEST: Investigators believe Aaron Alexis, a former Navy reservist, was the lone gunman in the shooting spree at the Navy Yard in Washington D.C. yesterday in which 12 people were killed before the suspect was killed in a firefight with police. The 12 deceased shooting victims range in age from 46 to 73 years old, Washington D.C. Mayor Vincent Gray said at an evening news conference. "We have no evidence that any active military are among the victims," Metropolitan Police Chief Cathy Lanier said. Officials said three others suffered gunshot wounds and five more people suffered other injuries. Police identified the seven victims whose families had been notified as: Michael Arnold, 59; Sylvia Fraiser, 53; Kathy Gaarde, 62; John Roger Johnson, 73; Frank Kohler, 50; Kenneth Bernard Proctor, 46; and Vishnu Pandit, 61. The death of Alexis, 34, of Fort Worth, Texas, brought the toll of the carnage at the Navy Sea Systems Command headquarters to 13. The suspect had a security clearance that allowed him onto the Navy Yard as part of his civilian subcontracting work, officials said. http://abcn.ws/182DaMp

• NINE MONTHS AFTER NEWTOWN: Gun control advocates making their last-minute preparations for a lobbying trip to Capitol Hill were shaken by the mass shooting at the Navy Yard, but they say they are determined to continue their push for stricter legislation, ABC's ABBY PHILLIP reports. Nine months after the Sandy Hook Elementary School massacre left 26 dead, including 20 children, many of those grieving families, as well as families and victims of other gun related tragedies planned to return to Washington to try to jumpstart an issue that seems to have lost some of the urgency it had. "It all comes flooding back to you," said Darren Wagner, the father of two children who survived the Newtown, Conn., shooting. "It makes me angry as a dad, as a police officer, as a first responder." http://abcn.ws/183F4MW

• ON THE HILL: More than 90 advocates with Newtown Action Alliance are scheduled to arrive in Washington today in a pre-planned trip to jump start conversations in Congress on background check legislation. They have more than 40 meetings planned with Congressional offices this week, and plan to hold a press conference with Newtown families on Wednesday. A rally with gun control group Mayors Against Illegal Guns is planned for Thursday. With Congress officially back in session after the August recess, they hoped to keep the pressure up on lawmakers to support a second attempt at national background check legislation after the first attempt failed in April.

• TODAY AT THE WHITE HOUSE: President Obama has no public events on his schedule today, ABC's DEVIN DWYER notes. He meets for lunch with Vice President Joe Biden, holds a private credentialing ceremony for a handful of ambassadors and meets with Defense Secretary Chuck Hagel.

THE ROUNDTABLE

ABC's RICK KLEIN: This time, even the trite commentary - "the world is different now," or "everything's changed" - isn't being offered. The fact is, it isn't, and it hasn't. President Obama yesterday hinted at his frustration at responding to "yet another mass shooting," though he stopped short of using it to renew his calls for expanded background checks or other new gun-control measures. That will surely change, and others will fill the void in a week heavy with gun-related events at the Capitol; Newtown families and relatives of Chicago gun-violence victims were long scheduled to be in Washington this week. But does anyone realistically think the stubborn politics of gun control will change after this mass shooting, or the next or the one after that? In retrospect, the last best shot for meaningful changes to federal gun laws almost certainly came back in April, when the bipartisan background-checks deal came within five votes of passing the Senate, while memories of the deaths of 20 schoolchildren in Connecticut were still fresh. Sadly, there will be no shortage of new moments to focus on guns. But the overwhelming likelihood is that this Congress had its moment for action already.

ABC's DEVIN DWYER: Fourteen months ago, President Obama put politics on pause in the immediate aftermath of one of the worst mass shootings of his presidency. When 12 people were shot and killed inside an Aurora, Colo., movie theater, Obama pulled his campaign TV attack ads off the air the same day, cancelled surrogate events and turned a planned rally of his own into a solemn moment of reflection: "There are going to be other days for politics," he told the crowd in West Palm Beach, Fla., on July 20, 2012. On Monday, Obama appeared to set that axiom aside. As another mass shooting was unfolding, with 12 more shot and killed less than 3 miles from the White House, the president proceeded with a planned economic speech that spent much of the 23 minutes sharply criticizing congressional Republicans for positions on the federal budget and debt ceiling. (You can read the speech: http://1.usa.gov/16dmvSy) It largely went unanswered, with Hill leaders canceling all planned votes, debates and photo ops for the day in light of the shooting. "It's a shame that the president could not manage to rise above partisanship today," said House Speaker John Boehner in a statement. White House spokesman Jay Carney said no consideration was given to postponing Obama's remarks because of the urgency of looming fiscal deadlines. "It's entirely appropriate today for the president to talk about that," Carney said. "Congress needs to act. It has some very clear top-line responsibilities: fund the government, pass bills that pay for the activities of the United States government. They insisted on a process whereby budgets were passed in the Senate and the House, and now Republicans have blocked the process of reconciliation," he said. "So time is short. We need to address these challenges."

BUZZ

D.C. GUN LAWS SOME OF THE STRICTEST IN THE U.S. The mass shooting Monday at the Navy Yard is the deadliest shooting in the country so far this year, yet it occurred in a city that according to gun control advocates has some of the strictest gun laws in the country, ABC's ABBY PHILLIP writes. Even though the Supreme Court struck down D.C.'s ban on the possession of handguns in the home in 2008, the District still has a litany of laws on the books that make it more difficult to obtain some firearms, impossible to obtain others, and illegal to carry any loaded gun in the city. By just being in the city with a loaded firearm, regardless of whether he was the legally registered owner, the suspect Aaron Alexis would be in violation of D.C. law. Carrying a concealed firearm or carrying a firearm openly in D.C. are both against the law. Bringing a firearm from out of state without registering it in D.C. is illegal. Assault-style rifles are banned. And even traveling through D.C. with a firearm is illegal. In addition, the Navy Sea Systems Command headquarters is a federal facility that is subject to federal law, which prohibits carrying a firearm onto the premises (except by law enforcement or members of the armed forces). Gun-rights advocates frequently suggest that tough gun laws don't make people safer. In 2012, D.C. reported fewer than 100 homicides for the first time since 1963. Here's an overview of some of D.C.'s gun rules: http://abcn.ws/1ekZRzV

POLL: WITH POOR RATINGS ON HANDLING SYRIA, OBAMA'S APPROVAL WORST IN OVER A YEAR. Barack Obama's job approval rating flattened at an even 47-47 percent in the latest ABC News/Washington Post poll, his lowest in more than a year, with more than half of Americans disapproving of his handling of the situation with Syria, ABC's GARY LANGER writes. The public by a 15-point margin is more apt to say Obama's performance on Syria has weakened rather than strengthened U.S. global leadership, and six in 10 continue to oppose the missile strikes he urged. At the same time, the survey finds vast support, 79 percent, for the Russian-backed plan to junk Syria's chemical weapons, even amid skepticism Syria will cooperate. If Syria in fact fails to surrender its chemical weapons, the public divides about evenly on whether Congress should authorize military strikes after all: Forty-four percent say it should, short of a majority but well more than the 30 percent who back missile strikes as things stand now. http://abcn.ws/182N54H

-BEHIND THE SYRIA NUMBERS: Most import on Syria is the question of whether or not the situation involves the vital interests of the United States, as Obama has argued. Support for strong action rises in cases when U.S. interests are seen as being at stake; for instance, 67 percent said so about Iraq in 2003, vs. just 23 percent about Somalia in 1993. On Syria, it's a split decision: Forty-five percent of Americans see vital U.S. interests at stake in this situation, while 48 percent do not. Liberals are most likely to see the issue as one of vital concern, with 55 percent saying so; fewer moderates and conservatives agree, 43 and 42 percent, respectively. It matters: People who see vital U.S. interests at stake are 16 points more apt than others to favor missile strikes now (though most still don't) and 23 points more apt to favor having Congress authorize military action if Syria fails to cooperate. Should Syria stall, support for congressional authorization reaches 56 percent among people who think vital U.S. interests are involved, vs. 33 percent among those who think not. http://abcn.ws/182N54H

OBAMA OKS CHEMICAL WEAPONS AID TO SYRIA. President Obama formally authorized American shipments to Syria of non-lethal equipment and supplies specifically aimed at countering the threat of Bashar al-Assad's chemical weapons as the world waits for them to be neutralized, ABC's DEVIN DWYER and JONATHAN KARL report. In a signed order, Obama yesterday waived prohibitions of such shipments by the Arms Export Control Act, determining that the assistance is "essential to the national security interests of the United States." The materials - including chemical weapons-related personal protective gear and medical supplies - will be sent to "vetted" members of the Syrian opposition, international aid groups inside Syria, and any other organizations working to "prevent the preparation, use, or proliferation of Syria's chemical weapons," an administration official said. Among the groups expected to receive the aid is the Organization for the Prohibition of Chemical Weapons, the group expected to lead any monitoring and enforcement effort under the deal to transfer stockpiles under international control. http://abcn.ws/15ysvc6

POLL: FIVE YEARS AFTER THE ECONOMY'S MELTDOWN, MOST STILL SEE INADEQUATE SAFEGUARDS. Five years after the economy fell into the abyss, fewer than half of Americans feel it's improved substantially - and two-thirds in a new ABC News/Washington Post poll say the federal government has failed to take adequate steps to prevent another meltdown, according to ABC's GARY LANGER. As Barack Obama today marks the anniversary of the Lehman Brothers collapse by heralding economic gains, 51 percent disapprove of how he's handled the economy, vs. 45 percent who approve. Obama hasn't received majority approval for his economic stewardship in ABC/Post polls since November 2009, back in the first year of his presidency. But there's skepticism to share. Despite his weak rating, Obama narrowly leads the Republicans in Congress in trust to handle the economy, 44-38 percent. And while 66 percent say the federal government hasn't taken adequate steps to prevent another crisis, about as many, 62 percent, say the country's financial institutions also have failed to put sufficient safeguards in place. http://abcn.ws/150O3un

WHO'S TWEETING?

@chicagotribune: Bill Daley to explain his reasons this morning for dropping out of the Illinois governor's race http://trib.in/18upOur

@DavidMDrucker: . @PRyan predicts no govt shutdown-& tries to clear up "misconception" that defunding #Obamacare is realistic: http://m.washingtonexaminer.com/paul-ryan-house-gop-searching-for-achievable-obamacare-strategy/article/2535880 …

@robertcostaNRO: Rush says there's an "all-out assault against Ted Cruz… within the Republican party" http://www.youtube.com/watch?v=VU1RgKFrslY&feature= …

@markknoller: In speech prepared for Econ. Club of DC, Lew says if Congress fails to act & US cannot pay its bills, "the repercussions could be serious."

@GlennThrush: Local media gonna question the incomplete, shoddy, contradictory briefings given by Lanier & Gray yesterday? Never seen anything like it.