News Analysis: U.S. presidential candidates Trump, Sanders could last longer than expected

The two most radical candidates in the U.S. race for the White House next year may be more than a flash in the pan, as many analysts believe they could last longer than previously expected.

Both Senator Bernie Sanders, running for the Democratic nomination, and billionaire mogul Donald Trump, running for the Republican nomination, have surprised many.

While observers, experts and political prognosticators initially predicted they would fade out, Trump continues to lead the pack of Republicans and Sanders continues to draw large crowds at rallies.

Indeed, experts said the two candidates have tapped into Americans' populist anger at the status quo, as many see the United States as going down the wrong path, and believe that Congress, the White House and the other 2016 presidential candidates do not represent the interests of ordinary Americans.

By sharp contrast, Trump and Sanders, while at opposite sides of the political spectrum, have resonated with their fans for being straight and honest and not speaking in canned statements or couching their language in political correctness.

While their policies are seen as extreme -- Sanders is a socialist and Trump wants to pressure Mexico to pay for a wall on the United States' southern border to keep out illegal immigrants -- their messages resonate with many Americans.

Some experts believe the candidacies of Sanders and Trump, because they are so radical and because they appeal to the anger and frustration of many Americans, are likely to be in the race for some time to come.

"Trump and Sanders could retain their popularity for a number of months because the issues they have identified are long-term in nature and not likely to go away any time soon," Brookings Institution's senior fellow Darrell West told Xinhua.

"Each of them has tapped into voter anger and identified issues that frustrated many Americans. For Trump, it is the immigration issue and the large number of people in the United States without proper documentation. For Sanders, the key issue is income inequality and loss of social and economic mobility," West said.

Indeed, Trump has put the immigration debate at the forefront of his campaign, calling for the deportation of the millions of illegal immigrants in the United States, and that has gained him admiration from more conservative voters. Meanwhile, Sanders has made an issue of the fact that millions of Americans are struggling to get by.

"I expect each of them to do reasonably well in the primaries because there is an electoral niche for what they have to say. That could keep them in the race for a long time," West said.

Currently, Trump leads the list of more than a dozen other Republican candidates by 22 percent, according to the latest Real Clear Politics poll average. Former Florida Governor Jeb Bush, who experts just a few months ago predicted would be a shoo-in for the Republican nomination, trails behind at less than half that number.

For his part, Sanders trails Democratic front-runner Hillary Clinton by 24 points, according to the same polling average, but at the same time seems to be generating more excitement among his followers.

Moreover, many experts said the controversy over whether Clinton's use of a personal email account while she was secretary of state compromised U.S. national security could become a major thorn in her side.

Depending on what will unfold as the U.S. Federal Bureau of Investigation concludes its current investigation into Clinton, the former first lady could see some of her base defect to the Sanders camp, experts said. Endi