Interference by Nevada lawmakers and the White House “tainted the administrative process” that led the U.S. Department of the Interior to withhold approval of the Mashantucket Pequot Tribe’s amended gaming agreement with the state, a new court filing alleges.

The state and the tribe are seeking to amend their lawsuit over Interior’s failure to approve the agreement, inaction that has derailed the Mashantucket and Mohegan tribes’ joint venture to develop an East Windsor casino.

In the filing Wednesday in U.S. District Court for the District of Columbia, the state and the Mashantuckets claim Interior officials were preparing to approve gaming agreements that each of the tribes had reached with the state when “the (Interior) Department ultimately buckled under undue political pressure from both Senator Dean Heller and Representative Mark Amodei,” both of whom are Nevada Republicans.

The filing says MGM Resorts International, the Las Vegas, Nev.-based casino operator seeking to block the East Windsor project, is a major campaign contributor to Heller and Amodei.

Heller, the filing alleges, “directly pressured” Interior Secretary Ryan Zinke “to do what was necessary to stop the Tribes’ joint venture casino project during a private dinner at a steakhouse in Las Vegas, Nevada, on or about July 30, 2017.”

According to the filing, both Heller and Amodei subsequently pressured Interior officials to change the department’s position and that Zinke visited the White House to meet with Deputy Chief of Staff Rick Dearborn, “who, exerting Executive-level pressure, requested the Department to not approve the Tribal-State Agreement.”

An Interior official wrote letters to the tribes in September 2017 informing them that action on their gaming-agreement amendments was “premature and likely unnecessary.” Two months later, the state and the tribes sued, arguing that federal regulations compelled Interior to act within 45 days of receiving the amendments or to consider the amendments “deemed approved.”

“Knowing that this unfounded reversal in course ... was unsupported by law or fact, Secretary Zinke refused to take calls from the Tribes regarding the Department’s decision, which, upon information and belief, he dubbed the ‘MGM matter,’” the latest filing says.

Interior acknowledged the Mohegans’ gaming amendment, publishing notice of it June 1 in the Federal Register, which prompted the Mohegans to withdraw from the suit. Interior has never acted on the Mashantuckets’ amendment, claiming it was not required to do so because of the way in which the Mashantuckets' original agreement with the state was reached.

While the Mohegans’ agreement is considered a tribal-state “compact,” the Mashantuckets’ agreement was “prescribed” by the Interior secretary. The state and the Mashantuckets contend the tribes' agreements “function identically in the real world” and that Interior is violating federal law by treating them differently.

In a Sept. 29 ruling, Judge Rudolph Contreras dismissed the state and the Mashantuckets’ claim and granted MGM Resorts’ request that it be allowed to intervene in the case should it continue. Contreras found that MGM Resorts had “standing” because the tribes’ East Windsor project “would expose MGM to added competition.” The Las Vegas operator recently opened a casino in Springfield, Mass., and has proposed one for Bridgeport.

“The Tribe's request to amend its complaint is a meritless attempt to avoid the Court's recent ruling dismissing its lawsuit,” MGM Resorts said in a statement. “Having lost that case, the Tribe is now attempting to repackage the same unfounded arguments using different language. Even if the Court grants this procedural request, we are confident that the Court will reject those claims on the merits, regardless of how many different ways and times the Tribe tries to make the same argument."

“This is like a student asking for a do-over after failing a test," the statement says.

Links between MGM Resorts’ lobbying efforts and the Nevada lawmakers were first reported earlier this year by Politico, prompting Connecticut lawmakers to ask that the Interior Department's inspector general investigate the department’s handling of the tribes’ amendments. The probe is ongoing.

b.hallenbeck@theday.com