Some observers question whether U.S. Vice President Joe Biden has enough time to put together an effective presidential campaign. Pictured: Biden pauses as he delivers remarks at the U.S.-Ukraine Business Forum in Washington, July 13, 2015. Reuters

Amid growing scandals and increasingly weak polling, former Secretary of State Hillary Clinton's presidential campaign has become a cause for concern for some Democrats who are finding themselves tempted by a different politician who has also been on the national scene for decades: Vice President Joe Biden.

Biden, who had until recent weeks been coy about his White House ambitions, appears to be quietly considering a presidential run. But if he were to enter the race, he would have a steep hill to climb to beat Clinton, who has had a head start raising campaign cash and winning over important supporters. No matter the latest poll data, Biden might be running out of time to launch a candidacy, political analysts said.

"One of the first campaigns I consulted on, the campaign manager told me, 'You can always raise a little more money, recruit a few more volunteers, but you can't put more days on the calendar,'" said Brad Bannon, a Democratic strategist in Washington, D.C. "Putting together a national campaign is a real tough thing. You have to put the pieces together, then you have to roll it out and then after that problems will occur and you work the kinks out. You've got to give yourself time to do that."

U.S. Vice President Joe Biden reportedly has received President Barack Obama's blessing to launch a presidential campaign. Pictured: Biden looks on as Obama delivers a statement about the Iran nuclear deal at the White House, July 14, 2015. Reuters

Biden's most pressing obstacle is cash. He'd need to raise enough money to combat what is expected to be a historic level of cash raised by the Clinton campaign. On Monday, the Washington Post reported that he had invited top Democratic fundraisers to meet him at his vice presidential home, the Naval Observatory. Among those invited were big bundlers for the Obama-Biden tickets in 2008 and 2012.

But Biden may have a hard time winning over big donors who have already signaled support for Clinton.

"Even for those that may be inclined to switch their support to Biden, they're going to want to see tangible progress before they throw their hat in the ring with them or else they're just going to unnecessarily upset the Clinton campaign," said Jim Manley, a Democratic strategist who is on the record supporting Clinton's candidacy and participates on conference calls with the campaign.

To show campaign donors and operatives he is serious, Biden would need to put together campaign organizations in early primary states like New Hampshire and Iowa, where he could organize grassroots efforts to attract voter support. Biden also would need Clinton to keep dipping in the polls, burdened by concerns about her use of a private email server while secretary of state. October could prove to be an important month for the two politicians in that sense, as Clinton is expected to testify before the House Select Committee on Benghazi, the attack on a military compound in Libya in September 2012 that killed four Americans, including U.S. Ambassador Chris Stevens.

Biden could potentially tap into a populist sentiment building in the electorate that has seen Donald Trump win over Republican voters and Sen. Bernie Sanders make surprising gains against Clinton on the Democratic side. Over the weekend, Biden had a private visit with Sen. Elizabeth Warren, a favorite of the far left, a sign that he may be courting her endorsement and core supporters who see Clinton as too much of a political insider. Biden also recently met with President Barack Obama during their weekly lunch, during which Obama reportedly gave his blessing to the vice president's potential campaign.

"There’s a populist trend going on that is not respectful of party hierarchy structure or the normal rules of political discourse," said Hank Sheinkopf, a Democratic strategist who advised former President Bill Clinton. "And, Joe Biden understood that: He knows how to tap into it without thinking about it."

Facing concern over her private emails and public image in general, Clinton's polling has plummeted since her peak in May, when she received 64.2 percent of the Democratic vote. She's currently polling at 49.3 percent in an average of polls, and has seen Sanders gaining on her. He is currently polling at 25 percent and Biden is at 12. Biden, however, is currently polling more favorably in key swing states like Pennsylvania, Florida and Ohio, while Clinton is deep underwater with unfavorables over 50 percent. Biden is also polling a bit better than Clinton against potential Republican challengers in those states, too.

"If she keeps getting banged around in the press and the server business becomes explainable to the average citizen" it's unclear if Clinton can maintain her lead in the polls, said Hank Sheinkopf, a Democratic strategist. "Five minutes in politics is 50 years in anything else, but if it looks like she's going to implode, he's going to have an opportunity."

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