Bernie Sanders expands campaign staff and boosts spending after Hillary Clinton pulls further ahead

Democratic presidential candidate Bernie Sanders is boosting the size of his campaign staff and increasing state budgets in his challenge against the frontrunner for the party's nomination, Hillary Clinton.

Over the past six weeks, Clinton widened her lead over Sanders in opinion polls both nationally and in early states in the nominating process for the 2016 presidential election. She now leads Sanders by 20 points nationally, with the support of 54 percent of Democrats versus 34 percent for the U.S. senator from Vermont, according to the most recent Reuters/Ipsos polling.

Sanders' campaign manager Jeff Weaver told Reuters that the campaign rewrote its budgets last week, doubling them to add more staff in each of the states holding nominating contests on March 1.

A dozen states hold votes that day and award delegates on a proportional basis rather than awarding all to the winner, so Weaver said the campaign calculated that it is important to compete hard in all of them rather than skip states where Sanders may not perform as well as Clinton.

Weaver said the campaign has also begun adding two dozen additional paid field staffers in the first contest in Iowa, which holds caucuses on February 1.

Clinton has capitalized on a series of strong debate performances, and she received wide praise for enduring 11 hours of questioning during an October congressional hearing about her handling of the attacks on U.S. diplomatic facilities in Benghazi in 2012. As a former secretary of State, she is seen as the strongest candidate to handle matters of international consequence.

The recent attacks in Paris are helping her in the Democratic primary race, said Democratic pollster Tom Jensen of the firm Public Policy Polling.

"Eighty percent trust her most on national security," Jensen said.

Even as the national conversation is moving toward those issues, Weaver said other metrics show Sanders is on the rise in the Democratic primary electorate, especially among voters who care about economic issues. In a Quinnipiac poll of Iowa Democrats released on Wednesday, 47 percent said they trusted Sanders most to handle the economy compared to 42 percent for Clinton.

"I think we're getting a second look," he said.

In an effort to try to erase Clinton's hefty lead with Latino voters, the Sanders campaign has begun airing Spanish language radio ads and delivering Spanish language mailings to Democratic voters in Nevada.

For more on the 2016 U.S. presidential race and to learn about the undecided voters who determine elections, visit the Reuters website. (https://www.reuters.com/election2016/the-undecided/)

(Reporting by Erin McPike; Editing by Andrew Hay)