For what might be the first time in this campaign, Republican front-runner Donald Trump shared an opinion that supporters of Senator Bernie Sanders are likely to agree with on Tuesday when he said Sanders has been treated unfairly by Democrats and should run as an independent candidate.

"Bernie Sanders has been treated terribly by the Democrats—both with delegates & otherwise," he said in a tweet. "He should show them, and run as an Independent!"

Bernie Sanders has been treated terribly by the Democrats—both with delegates & otherwise. He should show them, and run as an Independent! — Donald J. Trump (@realDonaldTrump) April 26, 2016

While he hasn't gone so far as to threaten a third-party run, Sanders doesn't appear prepared to enthusiastically endorse Clinton if she wins the nomination. When asked at an MSNBC town hall on Monday if he would tell his supporters to back Clinton if he's not on the ballot come November, he stopped short.

"We're not a movement where I can snap my fingers and say to you or to anybody else what you should do, that you should all listen to me. You shouldn't. You make these decisions yourself," Sanders replied.

RELATED: Check out the latest power rankings to find out who's most likely to be the next president



5 PHOTOS April 26 Presidential Power Rankings (BI) See Gallery Trump calls for Sanders to 'run as an Independent' 5. John Kasich, Republican, Ohio governor Kasich picked up momentum last month with a win in his home state's primary. But the road before, and since, has been virtually empty for the Ohio governor. He has no chance to accumulate enough delegates to clinch the nomination before the convention, so he's banking that he can win a floor fight. Kasich's rivals have seemed to grow increasingly frustrated with his presence in the race — Trump said he would "automatically win" if Kasich were to drop out of the race. Cruz, meanwhile, has shifted his stance on Kasich's presence in the race, teaming up with the Ohio governor in a last-ditch effort to stop Trump. Those who talk up Kasich say he is a successful governor of a swing state with a record to point to and clear bipartisan appeal. He also has abundant experience from nearly two decades in Congress, including foreign-policy areas and his time as chair of the US House budget committee. But that same bipartisan brand has hurt Kasich with the GOP base. He is to the left of most GOP candidates on immigration reform, and he expanded the federal Medicaid program under the Affordable Care Act — two issues that could doom him with hard-line conservatives. National polling average among Republican voters: 22.3% (3rd)

Average in Pennsylvania, Maryland, Connecticut, and Indiana polls: 23.9% (3rd) DELEGATES: 148

STOCK: Falling

Last month: 5 (Photo via REUTERS/Carlos Barria) 4. Bernie Sanders, Democrat, senator from Vermont Sanders had perhaps the best single day of his campaign late last month, romping to landslide victories in Alaska, Hawaii, and Washington. But he got tripped up in New York, with a bigger-than-expected loss to Clinton in her adopted home state. And he faces challenging odds — he needs to win about 71% of the remaining pledged delegates to overtake Clinton in the pledged-delegate count, according to NBC. Moving forward, the map doesn't look especially favorable. In a system in which delegates are allocated proportionally, it will be hard for him to make up real ground in large states like California, Pennsylvania, New Jersey, and Maryland. National polling average among Democratic voters: 46% (2nd)

Average in Pennsylvania, Maryland, Connecticut, and Indiana polls: 40% (2nd) DELEGATES: 1,153

STOCK: Falling

Last month: 4 (Photo by Scott Eisen/Getty Images) 3. Ted Cruz, Republican, senator from Texas Cruz always had favorable ground in Wisconsin. After that, the map was supposed to get more challenging — and it has. Late April has overwhelmingly featured Northeast and mid-Atlantic contests more favorable to Trump — including delegate-rich New York, which Trump won with more than 60% of the vote. With more states from the regions on the map to come, Indiana's May 3 primary is looking more and more like a must-win for the Texas senator. Still, Cruz inspires a flood of enthusiasm among the GOP base, and he may be the best-positioned candidate from within the political sphere to back up the notion that he's not a typical politician, that he is the outsider the base wants despite his day job in Washington. National polling average among Republican voters: 30.3% (2nd)

Average in Pennsylvania, Maryland, Connecticut, and Indiana polls: 24.7% (2nd) DELEGATES: 559

STOCK: Falling

Last month: 3 (Photo via REUTERS/Aaron P. Bernstein) 2. Donald Trump, Republican, businessman Trump has lit the political world on fire since his entry into the race last summer, and he has showed surprising staying power. We're now on month No. 11 of "The Trump Show." He has won a majority of contests so far, a feat unthinkable when he entered the race in June. He appears poised to at least enter the convention with the most delegates of any Republican candidate — and after a gigantic win in New York, he seems better positioned to capture the nomination heading into the convention. There's a clear appetite among Republican primary voters for someone like Trump, who entered the race to controversy surrounding his position on illegal immigration. Business Insider discovered more of that when we followed him on the trail for a week last year. National polling average among Republican voters: 42.3% (1st)

Average in Pennsylvania, Maryland, Connecticut, and Indiana polls: 44.6% (3rd) DELEGATES: 845

STOCK: Rising

Last month: 2 (Photo via REUTERS/Eduardo Munoz) 1. Hillary Clinton, Democrat, former secretary of state The delegate math is on Clinton's side going forward, especially now that she has avoided her biggest potential pitfall in the New York primary. The long-presumed Democratic nominee, Clinton has been a shakier-than-expected candidate. But she has a clear look at the nomination, and she would enter the general election with a slight advantage over Trump — or Cruz. "I'm not going to be responding to him," Clinton said in a recent interview with Business Insider. "I have pretty thick skin. I've been in the arena a long time, and that means that I am not going to get down with him and go insult for insult." Check out that full interview here. National polling average among Democratic voters: 49.3% (1st)

Average in Pennsylvania, Maryland, Connecticut, and Indiana polls: 51.9% (1st) DELEGATES: 1,428

STOCK: Rising

Last month: 1 REUTERS/Charles Mostoller Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Tuesday's tweet is far from the first time Trump has complained about the primary process and rules -- although the majority of his complaints up until now have been directed at the Republican Party.

Over the weekend Senator Ted Cruz and Ohio Governor John Kasich announced a joint "stop trump" partnership, saying they would stay out of each other's way in some upcoming state primaries. "Our goal is to have an open convention in Cleveland," Kasich's chief strategist John Weaver said in a statement. However latest reports indicate that the strategy may already be splintering.

SEE ALSO: Ku Klux Klan claims $20K in Clinton donations

Trump's comment toward Sanders came as voters were casting ballots in both the Democratic and Republican primary races in Connecticut, Maryland, Pennsylvania, Rhode Island and Delaware.

Clinton was considered the favorite in most states going into Tuesday, but polls show Sanders only a few points behind her in a handful of states -- meaning he could snag a victory or two on Tuesday.

But because of how the delegate math works, Clinton is still favored to make big gains. She is expected to walk away with 219 delegates, while Sanders is predicted to score 165, according to FiveThirtyEight.com. If all goes as predicted, Clinton's delegate lead would be almost 300.

SEE ALSO: Republicans Cruz, Kasich reach 'stop-Trump' deal

Sanders himself has not had many kind words for Trump in the past.

"We are not going to elect a President who insults people, every single day," Sanders said to supporters at a rally in March. "The American people will not elect Donald Trump president because he insults Mexicans; he insults Muslims; he insults women; he insults veterans; he insults the African American community."

RELATED: Check out the books the candidates have written



More from :

Sanders campaign manager vows convention fight

Sanders raises more cash but Clinton makes campaign dollars go further

Bernie Sanders blames primary losses on 'sad reality' that 'poor people don't vote'