As Hillary Clinton's lead grows, does Bernie Sanders have a chance?

Two major polls show Hillary Clinton well ahead of her chief rival, Sen. Bernie Sanders, among Democrats and Democratic-leaning voters.

Days ahead of the second Democratic presidential debate in Iowa, Hillary Clinton's comeback appears stronger than ever as two recent polls show she is leading the field by large margins thanks to a series of recent coups in her campaign.

Some 52 percent of Democratic primary voters support Mrs. Clinton, while 33 percent support Sen. Bernie Sanders, according to a New York Times/CBS News survey released on Thursday. Former Maryland Gov. Martin O’Malley is trailing far behind his rivals, with 5 percent of the vote.

There's more good news for Clinton: Her net favorable rating among Democrats and Democratic-leaning voters is 63 percent, up from 49 percent just before the first Democratic debate, according to a Nov. 9 Gallup poll. Senator Sanders is trailing here, too, with a net favorable rating of 38 percent, down 1 percentage point since the last debate.

After a summer-long sag in the polls, these latest numbers reflect a series of positive developments for Clinton in recent weeks. Her strong performance at the first Democratic debate, Vice President Joe Biden’s decision not to enter the race, and a well-received testimony to a House committee investigating the 2012 attack on the United States diplomatic compound in Benghazi, Libya, have all helped buoy Clinton's campaign.

"This isn’t entirely unexpected for people who have been watching the polls and looking at the fundamentals of the campaign," Frank Orlando, a political scientist at Saint Leo University in Saint Leo, Fla., told The Christian Science Monitor in an earlier story on Clinton's comeback. "When you are the frontrunner you are going to get heat – from Republicans and Democrats alike. Clinton has gone through a period in the campaign where she has undergone a great amount of scrutiny, and some of this was self inflicted. Clinton’s numbers swooned a bit."

Now, she appears to be stronger than at almost any other point since she declared her candidacy.

Her supporters appear to be more enthusiastic. Some 43 percent of Democrats said they would enthusiastically support Clinton as their presidential nominee, compared to 35 percent for Sanders, according to the NYT/CBS poll.

Her supporters are also more resolute in their support. Some 54 percent of her supporters said their minds were completely made up, while 58 percent of  Sanders’s supporters said they had not made a final decision.

In fact, Clinton is more well-liked among liberals than Sanders, a self-described democratic socialist, with the former secretary of State holding an 11-point lead in favorability among liberals, according to Gallup.

She'll have a chance to further establish her lead, and Sanders will have a chance to increase his support, at the second Democratic debate Saturday Nov. 14 in Des Moines, Iowa.

That's especially important for Sanders because the NYT/CBS poll suggested he has room to grow: About half of Democratic primary voters said it was still too early to say for sure who they would support.

So what can Sanders do to win over some of those undecided primary voters?

For starters, he'll have to work harder to woo minorities, especially black voters.

Clinton has a nearly 90 percent net favorable rating among African-Americans, according to Gallup. Sanders is a relatively paltry 21 percent. That may be partly due to the fact that 55 percent of black Democrats don't know enough about him to rate him. In contrast, 91 percent are familiar with Clinton, with almost all rating her favorably.

Sanders has long struggled to connect with black voters, a problem that was compounded by his botched response to Black Lives Matter protesters at a Netroots Nation conference in Phoenix over the summer. His home state, Vermont, is 95 percent white and many black voters simply don't know him.

He's trying to change that. He's rolled out a comprehensive racial justice plan, he met with prominent racial justice and Black Lives Matter activists, and he has made an effort to campaign directly in black communities around the country.

Sanders is also increasing his attacks on Clinton in recent weeks, stating in a Boston Globe editorial meeting last week that "I disagree with Hillary Clinton on virtually everything." He's also increasingly focusing on her controversial use of a private e-mail server while serving as secretary of State.

The Sanders camp did get a boost this month: The Vermont senator handily won Western Illinois University's mock election, which is billed as the largest in the country and correctly predicted the outcomes in both the 2008 and 2012 races.

And while Sanders may have his work cut out for him among Democratic voters, Clinton is far from home free.

She'll have to work hard to improve her image among Americans of all political persuasions. Her image among the general populace is still relatively weak, with 44 percent of Americans viewing her favorably, and 48 percent unfavorably.