Vice President Joe Biden is gearing up for a packed September schedule in his day job that could showcase him as the politician best poised to carry on President Obama's policies — or open him up to new lines of attack if he stumbles.

These include mid-September votes in Congress on an Iran deal that Biden has been deeply involved in promoting; visits to Washington by Pope Francis and Chinese President Xi Jinping; a looming budget showdown; and administration efforts on climate change, renewing the Export-Import Bank's charter, criminal justice reform and closing the terrorism detention facility at Guantanamo Bay, Cuba.

All could bolster Biden's credentials if he decides to challenge Hillary Clinton for the 2016 Democratic nomination for president — foreign-policy expertise from years running the Senate Foreign Relations Committee and powers of persuasion on legislation that Obama has often lacked.

"Any opportunity the American public has the chance to see the vice president lead portends well for him," said Steve Schale, an adviser to Draft Biden, a super-PAC encouraging Biden to run. "In a month of consequence, this will be a fine opportunity for the American people to confirm what they already know: that the vice president is an outstanding leader."

While Biden aides said he hasn't made a decision, the accelerated pace of his deliberations over the last two weeks are being read as signals that he is edging closer to a run.

Biden was back at the White House on Monday after weeks away at a South Carolina vacation spot and his home in Delaware that were punctuated by talks with top aides and some potential supporters on whether to run.

He joined Obama in the morning for the presidential daily briefing and for a private lunch before the president left for a clean-energy summit in Las Vegas.

Oct. 1 deadline to decide

People close to Biden point to Oct. 1 as a likely deadline for him to articulate his 2016 plans. The longer he waits, the harder it gets for him to put together a viable organization, raise money and qualify for primary ballots with deadlines in some states as early as November. Setting up an organization in a state may take a minimum of three to four weeks.

The Washington Post reported on Monday that major Democratic fundraisers have been invited to meet with Biden at his residence at the U.S. Naval Observatory after Labor Day, part of a series of conversations he is having with senior party players.

Among the guests invited are top bundlers who raised large sums for the Obama-Biden campaigns in 2008 and 2012, the Post reported.

If Biden's best chance of competing is Clinton's loss of support because of her handling of questions involving her use of a private e-mail server, some Biden backers say he may do better to ride out September and see how much worse it gets for her — that if he's waited this long a few more weeks won't matter.

There are two dates in October that do matter: Oct. 13, which marks the first Democratic presidential debate, in Nevada; and Oct. 22, the date Clinton is scheduled to testify before the House Select Committee on Benghazi.

Biden meets with Warren

Speculation about a Biden run spiked on Saturday after he interrupted his vacation to meet with Massachusetts Sen. Elizabeth Warren, a hero of the Democratic Party's progressive wing who has resisted calls to run herself.

The offices of Biden and Warren wouldn't comment, prompting speculation on the Sunday talk-show circuit.

James Carville, who has been an adviser to Clinton and former President Bill Clinton, suggested Biden probably wouldn't give Clinton a serious chase regardless of his timing, noting Biden's failed runs for the 1998 and 2008 nominations. "He's done it twice, and he hasn't had the best track record doing it," Carville said in a radio interview Sunday.