News Analysis: Donald Trump ahead in U.S. polls, but it may not last

While U.S. real estate magnate Donald Trump is leading among Republican presidential candidates in the polls, many doubt if he can really clinch the nomination.

The billionaire mogul stands nearly 5 points ahead of former Florida Governor Jeb Bush in a very crowded Republican field, in the lead-up to the 2016 presidential elections.

Trump is getting the attention of conservative voters, tapping their anger on a number of issues including illegal immigration and border security. But the question is whether this will last.

"The main virtue of Trump right now is his ability to stand out from a 16-candidate field. He will be in the top three candidates as long as he can hold 15 percent of the vote. However, as the field narrows, it will be difficult for him to rise beyond where he is right now," Darrell West, a senior fellow at Brookings Institution, told Xinhua.

"There is a ceiling above which he never will go and this will be a problem if he makes it into the final four in the nominating process," West said.

Should he not get the Republican Party (GOP) nomination and run as an independent, that will siphon off Republican voters and ensure a victory for top Democrat candidate Hillary Clinton. But while Trump is drawing much applause right now from the GOP base, experts said he is highly unlikely to beat Clinton.

"Donald Trump cannot defeat Hillary Clinton," West said.

"In the head-to-head match-ups, she beats him by almost 20 points. He would not be competitive with women, Latinos, or young people. His base is older, white men, and it would be difficult for him to move beyond that niche," West said.

Indeed, the GOP is in need of reform, say both experts and the party itself, as it is viewed as the party of older, white males and perceived, rightly or wrongly, as not friendly to single women or minorities. While the party has vowed to reverse this image, the GOP as of yet has taken little decisive action in that direction, critics say.

West noted that Trump's unfavorability numbers are sky-high and that he is a polarizing figure. "His personality attracts a certain percent of the vote, but it also repels many others," West said.

Trump has recently made a number of controversial remarks, such as comments about 2008 GOP presidential candidate John McCain's service in the U.S. war with Vietnam.

A Monmouth University poll released Tuesday found that Trump leads New Hampshire Republican votes with 24 percent support -- twice that of Jeb Bush.

However, while Trump does well with men who bill themselves as very conservative, he does not do as well with women. Endi