News Analysis: Hillary Clinton gets biggest boon to winning nomination after Biden's dropping out

U.S. Democratic front-runner Hillary Clinton got the biggest boon to her bid to clinch her party's nomination for the 2016 presidential race, after Vice President Joe Biden announced Wednesday his decision not to run for president.

"The road is clear for Hillary Clinton," Brookings Institution's senior fellow Darrell West told Xinhua. "Biden would have been a formidable opponent and would have taken several months to defeat."

Indeed, Biden's decision eliminates Clinton's most serious opponent and greatly simplifies her political situation, West said, adding that Clinton can now position herself for the general election and focus on issues that distinguish her from the radical elements within the Republican party.

Julian Zelizer, professor of history and public affairs at Princeton University, told Xinhua that Clinton will now be able to focus most of her attention on attacking the Republican Party (GOP) and building her message rather than competing with Biden for the same pocket of votes.

That will give her a leg up on Republicans, who must spend the coming months appealing to their party's base. And once a winner emerges, he or she will then begin to focus on beating Clinton.

"There will be states where Sanders may defeat her, but I would expect Clinton to accumulate delegates at a rapid pace and be in good position by the end of March," West said, referring to Senator Bernie Sanders, who recently has been seen as a possible rival, although most experts believe he will in the end be no real challenge to Clinton.

However, the Clinton campaign in recent months has seen a firestorm of controversy over her use of a private email account and private server as secretary of state, and she has been under investigation by the Federal Bureau of Investigation over whether she compromised national security. If that controversy continues to dog her, it could drag down her campaign.

West said the email scandal has been a major bump in the road for Clinton, but she has made progress in addressing that issue.

In another scandal over the 2012 terrorist attack on the U.S. consulate in Benghazi, Libya that led to the death of a U.S. ambassador and three other Americans, Clinton testified before Congress on Thursday, fighting allegations that she had mishandled the situation.

But many experts said the issue is unlikely to hurt her, as the situation is too complex for the average American voter to understand, and most voters in presidential elections tend not to focus on complex issues but rather vote for a candidate who they feel they can relate to.

Some pundits contended that during Wednesday's announcement Biden curiously talked about his beliefs in a speech that, in some sense, sounded like a man who might indeed decide to run later on. Some speculated there may be a small chance that Biden could jump back into the race if Clinton's campaign should falter.

But West said Biden has closed the door to a presidential run. Several states have filing deadlines coming up in November so if he were going to run, he would have to declare his intentions now and quickly put together an organization. It will be impossible for him to jump back in after those deadlines pass.

Going forward, the GOP candidate, if nominated, who would give Clinton the biggest challenge would be Ben Carson, a retired top surgeon who has gained popularity because of his status as a political outsider, as Americans are fed up with the Washington elite. In a head-to-head match-up, Carson beats Clinton by 4.8 points, according to Real Clear Politics' average of polls.

The other candidate, as of now, who could give Clinton a run for her money is former Florida Governor Jeb Bush, the son and brother of two former U.S. presidents. Clinton trails him by 1.6 points, according to Real Clear Politics' poll average. Former Hewlett-Packard CEO Carly Fiorina also leads Clinton by a point.

While the bombastic billionaire Donald Trump, now leading the Republican candidates, trails Clinton by 2.5 percent, most polls have a margin of error of a couple of points, which means Clinton is essentially neck-in-neck with a number of leading GOP candidates, experts said.

While Florida Senator Marco Rubio trails Clinton by 1.3 points in the same polling average, Zelizer tagged him as a potential threat.

"Marco Rubio remains a potential threat given his ability to package his candidacy as something new and something fresh for the party," he said.

Indeed, Rubio, the son of lower-income immigrants from Cuba, appeals to Americans' current anti-establishment sentiment, and could also make inroads with Hispanic voters, an increasingly important voting bloc. Endi