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Mississippi has no shortage of candidates seeking to win its two U.S. Senate elections and a broadly contested 3rd District House race this year, but with only a handful of exceptions, there has been a noticeable lack of fireworks.

The relative tranquility in the races has surprised local observers, who say it's the happy product of strong incumbents, narrowly avoided primary challenges, and policy agreements on key issues.

There have been some splashes of unexpected drama. Last month, actors Robert De Niro and Alec Baldwin helped host a pricey cocktail party in Manhattan for a Democrat campaigning in what is widely viewed as a futile effort to unseat Republican incumbent Roger Wicker in the Senate.

The party, which had suggested campaign donations ranging from $1,000 to $5,400 per person, benefitted Howard Sherman, one of six Democrats facing off in the June 5 primary, his campaign confirmed to The Associated Press. Sherman is married to actress Sela Ward, who had recurring roles in shows like "House" and "CSI:NY."

Sherman may have needed the out-of-state Hollywood help: He had been his own biggest political donor so far by a dramatic margin. A finance report showed that through the end of March, he had put $500,000 into his own campaign, and had received just one donation for $1,000. The source? His own campaign manager.

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Wicker took aim at the event in an email to supporters, calling Baldwin and De Niro "mega liberals" who don't respect the president. De Niro has said Trump is not welcome at his restaurants, and Baldwin has lampooned the president regularly on "Saturday Night Live."

But despite his opponent's high-profile support, Wicker, who faces one minor challenger in the GOP primary, hasn't seemed to have much cause for alarm. Polls show he is the overwhelming favorite in November.

de niro trump reuters

Actor Robert DeNiro, a frequent Trump critic, has appeared on "Saturday Night Live" as Robert Mueller. (Reuters)

"Wicker will simply shrug off any Democratic challenge," Geoff Pender, the political editor of Mississippi's Clarion-Ledger, wrote last week.

Remarkably, Wicker received a $5,000 contribution from Sherman last year, according to Federal Election Commission records. Sherman was registered to vote as a Republican in California until 2016.

Sherman has said he donated because Wicker was facing the prospect of a primary challenge at the time by Chris McDaniel, a tea party-backed state lawmaker who nearly unseated longtime U.S. Sen. Thad Cochran in a bitter 2014 Republican primary.

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Cochran resigned from the Senate in April after serving 40 years, citing health issues, and Republican Gov. Phil Bryant appointed the state agriculture commissioner, Cindy Hyde-Smith, to fill the Senate seat temporarily.

McDaniel had qualified to challenge Wicker this year, but switched races to challenge Hyde-Smith instead this November in a special election for the final two years of Cochran’s term.  There is no primary in the special election.

In May, a U.S. Chamber of Commerce poll showed that Hyde-Smith is significantly ahead of McDaniel and Democrat Mike Espy. Hyde-Smith commanded 30 percent of likely voters' support, with Espy at 22 percent and McDaniel at 17 percent.

McDaniel's decision to avoid a head-to-head with Wicker, which was all but assured to be yet another bruising primary battle, has contributed to an unusually quiet election season in Mississippi. McDaniel is not as well-funded as he was in 2014, the Clarion-Ledger reported, possibly leading to fewer aggressive advertisements and more positive campaign messaging overall.

The six Republicans and two Democrats vying for outgoing Rep. Gregg Harper's seat, meanwhile, are engaged in the "polite-est, least-contested contested primary in state history," Pender wrote, with nary a negative advertisement in sight.

"I moderated what was supposed to be a 'debate' among the GOP candidates, but they refused to debate," Pender continued. "Their policies and platforms appear to differ only in minute degrees."

The Associated Press contributed to this report.