Black Lives Matter has been the cultural and political story of the summer, at times managing to outstrip a pandemic and a presidential election for headlines as the movement led protests over racial injustice and animated the Democratic base -- yet high-profile BLM leaders are conspicuously absent so far from this week's national convention, underscoring the tension between the far-left political movement and the party.

The influence of Black Lives Matter on the Democratic convention, however, is apparent. Its platform in two separate spots says "we believe Black lives matter." Michelle Obama said "Black life matters" in her address (Sen. Bernie Sanders, I-Vt., who spoke before her Monday, did not).

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And the brother of George Floyd, whose death in the custody of the Minneapolis Police Department in late May served as the flashpoint that triggered nationwide unrest and the resurgence in the Black Lives Matter movement, asked for a moment of silence for his brother during his convention appearance.

The tension between Black Lives Matter and the Democratic Party has been clear all summer, with many activists associated with the movement demanding absolute ideological purity from officials on causes like defunding police, and Democrats, at times, not willing to oblige. No moment Monday underscored that dynamic more than when presumptive presidential nominee Joe Biden said police officers are generally good during a pre-recorded discussion on racial inequality.

The official Black Lives Matter Twitter account liked this tweet criticizing Joe Biden's comment that most police officers are good. (Screenshot/Twitter)

"Most cops are good, but the fact is the bad ones have to be identified and prosecuted and out period," Biden said.

That line upset many progressive activists, who said it missed the point they have been making -- that police, whether they as individuals have used unjustified force against Black people or are at their heart racists, are participating in the systemic oppression of Black people by simply being police officers. The A.C.A.B (All cops are bastards) acronym often seen at Black Lives Matter protests, Independent writer Victoria Gagliardo-Silver said earlier this year, "means every single police officer is complicit in a system that actively devalues the lives of people of color."

"Protestors haven’t been in the streets all summer because ‘most cops are good,'" activist Brittney Cooper wrote on Twitter Monday. "Do better, Dems." The official Black Lives Matter Twitter account liked that tweet.

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Cooper's other tweets from Monday night and Tuesday morning, however, were largely complimentary of the convention itself and urged people to vote for Biden, perhaps reflecting most progressives' desire to oust President Trump.

There are a handful of elected officials, like Rep. Alexandria Ocasio-Cortez, D-N.Y., scheduled to speak for one minute on Tuesday, who have vocally supported the movement. But the lineup that's been made public so far is heavy on current and former officials -- not unusual for a political party's convention -- who have not actively participated in the movement. None of the official speakers up Monday, or publicly scheduled to appear at the DNC Tuesday through Thursday, are leaders within the Black Lives Matter movement.

Fox News reached out to the DNC, the Biden campaign and Black Lives Matter to inquire whether any yet-to-be-announced speakers at the Democratic convention would be Black Lives Matter leaders or high-profile activists, but none immediately responded.

Even the speakers the DNC is featuring to highlight the message that Black lives matter, like Washington, D.C., Mayor Muriel Bowser, who spoke from Black Lives Matter Plaza, have been controversial within the Black Lives Matter movement. Bowser has been at odds with her city council over moves to defund the city's police, and said she doesn't think the city should have "a mob decide" to pull down historical statues. Bowser has even seen protesters march on her private property this summer expressing dissatisfaction with her handling of the recent unrest and reluctance to give in to their demands.

In another clash between a Democratic mayor and Black Lives Matter protesters this summer, Minneapolis Mayor Jacob Frey was booed out of a protest after refusing to commit to dismantling his city's police department.

"I do not support the full abolition of the Minneapolis Police Department," Frey said in response to a yes or no question on the matter.

"Alright, then get the f--- out of here," a protest leader yelled at him. "Go."

Similar hostilities have existed between Democratic Seattle Mayor Jenny Durkan and the city's Black former police chief, Carmen Best, who retired amid tension between her and the city government over support for police.

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And if the tension between the Democratic Party establishment and Black Lives Matter was in question, Black Lives Matter DC eliminated any uncertainty with broadsides against Bowser both Monday night and Tuesday morning.

"@MayorBowser is attempting to call out Trump’s treatment of protestors to distract from hers," the group said Monday night.

"@MayorBowser Hyprocrite morning to you!You literally gave your speech where u had DEFUND MPD paved over," Black Lives Matter DC said Tuesday morning. "41 Innocent Protesters where just beat, peppered sprayed & arrested last week.All Charges DROPPED. You or Paint don’t keep us safe."

Fox News' Adam Shaw contributed to this report.