FILE: Democratic presidential candidate Hillary Clinton speaks during a January town hall meeting at Woodbury School in Salem, New Hampshire. 

BOSTON – Hillary Clinton and Bernie Sanders are locked in a tight race for the Democratic presidential nomination ahead of next week’s Super Tuesday primaries. They remain close in the number of delegates they’ve won and in the latest polls.

Clinton, a former Secretary of State, picked up 90 delegates with wins eked out in the Iowa and Nevada caucuses and Saturday’s decisive victory in South Carolina’s primary. Sanders, a Vermont senator who won New Hampshire and placed second in Iowa, Nevada and South Carolina, has won 65 delegates to date.

In Massachusetts – which votes Tuesday with 11 other states and American Samoa – a recent Emerson College poll shows Clinton and Sanders tied with support from 46 percent of voters.

But the race between them is not nearly as tight in the tally that matters most for the nomination.

Clinton has racked up support of 459 superdelegates — elected officials and party elders who can support any candidate, regardless of the outcome of state primaries and caucuses — at July’s Democratic National Convention in Philadelphia. That includes another 6 superdelegates Clinton picked up in South Carolina.

Clinton’s haul, according to news reports, puts her at least 459 delegates ahead of Sanders in the Democratic party’s race for the White House heading into Super Tuesday.

And it sets her that much closer to the 2,383 delegate votes needed at the convention to win the nomination.

“Tomorrow this campaign goes national,” Clinton told supporters after Saturday’s win in South Carolina. “We are not taking anything, and we are not taking anyone, for granted.”

Sanders has only picked up pledges of support from 20 superdelegates, according to reports, putting his overall count at 85.

Political observers say Clinton’s superdelegate advantage means Sanders must win by big margins on Tuesday, when voters will award 974 delegates, if he hopes to overtake her in the race for the nomination.

“If Clinton wins big on Super Tuesday, the superdelegates could put her over the top,” said Mary McHugh, a political science professor at Merrimack College. “But even if she doesn’t, she still could ride to victory on the backs of the political establishment.”

Clinton’s collection of superdelegates includes a majority of the 25 from Massachusetts — including Sen. Edward Markey, D-Malden, Reps. Seth Moulton, D-Salem, and Niki Tsongas, D-Lowell, as well as former state Treasurer Steve Grossman.

“Clinton has a lot of support in Massachusetts, and that support runs deep,” Tsongas said. “But running for president isn’t easy, and she knows that she’s going to have to fight for every delegate and every vote if her campaign is going to be successful.”

Several state Democratic officials who are superdelegates — including Sen. Thomas McGee, D-Lynn, who is chairman of the state party apparatus — are remaining publicly neutral ahead of the primary. They’ve not declared whom they will support.

Those biding time include the state’s most notable superdelegate, Sen. Elizabeth Warren, who hasn’t endorsed anyone.

Every other member of the state’s all-Democratic, 11-member congressional delegation has pledged to support Clinton.

Clinton’s lead among superdelegates and her overall advantage — after voters in only three small states have cast ballots — has riled Sanders’ anti-establishment supporters, who accuse the Democratic Party and news media of trying to block his nomination.

A group of Sanders supporters started an online petition demanding that superdelegates align themselves with “regular voters” when casting nomination votes at the Democratic Convention. The group has collected nearly 200,000 signatures.

“Personally I can’t stand the term superdelegates — it smacks of elitism,” said Paul Kirk, a Barnstable Democrat and one of two superdelegates from Massachusetts who’ve publicly pledged to support Sanders. The other is Phil Johnston, former chairman of the state Democratic Party.

“But that’s how the system works,” he said.

Kirk, a former chairman of the Democratic National Committee who served as interim U.S. senator after Edward Kennedy’s death, downplayed the establishment support for Clinton.

Sanders has a foothold with the state’s progressive Democrats, he said, and he could peel away a few of Clinton’s superdelegates with a good enough showing among voters Tuesday.

“It’s important to realize that she locked down most of those superdelegates pretty early, even before the first votes were cast in Iowa,” Kirk said. “But there’s a real anxiety among Democratic voters that could end up driving them to Sanders in the end.”

“He’s going to be very competitive here and will pick up a few delegates,” he said.

Delegates awarded in about three-quarters of the country’s Democratic primaries and caucuses – including Massachusetts’ – are proportional to the outcome of the election.

In Massachusetts, that means Clinton and Sanders will share the 116 elected delegates up for grabs.

Even despite Clinton’s edge, Sanders was upbeat about his chances next week and beyond.

“This campaign is just beginning. We won a decisive victory in New Hampshire. She won a decisive victory in South Carolina,” Sanders said in a statement following Saturday’s primary loss. “Now it’s on to Super Tuesday. In just three days, Democrats in 11 states will pick 10 times more pledged delegates on one day than were selected in the four early states so far in this campaign. Our grassroots political revolution is growing state by state, and we won’t stop now.”

Superdelegates have been part of the Democratic Party’s nominating process since 1984, when the national committee adopted a rule reserving voting slots for members of Congress and state party leaders.

Superdelegates can support the Democratic candidate of their choice, regardless of whom primary voters support.

Nationally there are 712 Democratic superdelegates – about 30 percent of those delegates needed to clinch the nomination.

In 2008, the superdelegates’ vote was critical for then-candidate Barack Obama, who held a narrow, 127-vote lead over Clinton in the tally of delegates awarded by voters.

Republicans also have some automatic delegates but not nearly as many. GOP candidates need at least 1,237 delegates at their party’s convention in Cleveland in July to win the nomination for president.

Among Massachusetts Republicans, real estate mogul Donald Trump appears poised to handily win the state primary.

A recent Emerson poll shows the New Yorker commands a huge lead in the state with 50 percent of likely primary voters. Florida Sen. Marco Rubio trailed in second place with 16 percent, and Ohio Gov. John Kasich was third with 13 percent.

Trump, who won New Hampshire and South Carolina, has also dominated the contest for delegates, with 82 under his belt. Texas Sen. Ted Cruz has won 17 delegates, while Rubio has won 16 and Kasich has 6, according to a tally by CNN’s RealClear Politics.

The packed ballot means the state’s Republican establishment — which traditionally rallies behind a single candidate — is divided.

Gov. Charlie Baker, a Republican, endorsed New Jersey Gov. Chris Christie, who dropped out of the race after a disappointing, sixth-place finish in New Hampshire and winning fewer than 2 percent of the vote in the Iowa.

Baker has not yet endorsed another candidate and has said he is unlikely to do so before Tuesday, despite Christie announcing his support for Trump.

Christian M. Wade covers the Massachusetts Statehouse for CNHI’s newspapers and websites. Reach him at cwade@cnhi.com