The legal team representing Sen. Bernie Sanders' presidential campaign expressed opposition on Sunday to New York election officials' possible decision to remove the Vermont senator from the state's presidential primary ballot, a ploy that has angered progressives eager to help Sanders accumulate as many delegates as possible ahead of the Democratic National Convention.

With a vote on whether to remove Sanders from the ballot expected Monday, Sanders attorney Michael Seymour wrote in a letter (pdf) to the New York State Board of Elections—first obtained by HuffPost—that "Senator Sanders wishes to remain on the ballot, and is concerned that his removal from the ballot would undermine efforts to unify the Democratic Party in advance of the general election."

The New York primary is scheduled to take place on June 23.

"His involuntary erasure from the ballot, on grounds of a law that was not in effect when he announced his campaign's limited suspension, would sow needless strife and distrust, impeding Senator Sanders' efforts to unify the Democratic Party in advance of November elections."

—Michael Seymour, Sanders campaign attorney

Though Sanders suspended his presidential campaign on April 8, Seymour noted, Senator Sanders has not "officially terminated his candidacy with the Federal Election Commission" and has explicitly voiced his desire to "remain on the ballot in upcoming primaries, gather delegates, and attend the Democratic National Convention, with an eye to influencing the party's platform."

"His involuntary erasure from the ballot, on grounds of a law that was not in effect when he announced his campaign's limited suspension, would sow needless strife and distrust, impeding Senator Sanders' efforts to unify the Democratic Party in advance of November elections," Seymour wrote.

The law to which Seymour referred is a budget measure signed by New York Gov. Andrew Cuomo on April 13 that contains a provision empowering the state's Board of Elections to remove from the ballot candidates who have ended their presidential campaigns.

The language of the provision indicates that New York election officials have discretion to determine whether a candidate should be removed from the ballot: "The state board of elections may determine... that the candidate is no longer eligible and omit said candidate from the ballot."

As HuffPost reported, Board of Elections co-chair Douglas Kellner, a Democrat, "interprets that language to mean they're effectively required to remove Sanders."

Commissioner Andrew Spano, also a Democrat, has "expressed ambivalence... weighing the inconvenience to county governments against the desire of Sanders supporters for a 'voice at the convention,'" HuffPost noted.

To remove Sanders from the presidential primary ballot, both officials must agree to do so.

Seymour warned in his letter Sunday that Sanders' removal from the ballot would "undermine the Democratic Party's interest in self-governance and unification."

"Senator Sanders has complied with the state party's Delegate Selection Plan and with the national party's Delegate Selection Rules," said Seymour. "The party's rules do not permit, much less require, his involuntary removal from the ballot because of a public announcement of campaign suspension."

Read the full letter: