As one presidential candidate faces charges for spray-painting construction equipment at a Dakota Access Pipeline (DAPL) protest on Tuesday, many are calling for President Barack Obama and White House hopeful Hillary Clinton to make clear their own opposition to the controversial project.

"President Obama could step in any time and say 'no' to this whole thing—like he did for Keystone XL."

—350.org

Morton County Sheriff Kyle Kirchmeier said Tuesday that Green Party nominee Jill Stein would be charged for her participation in an action that saw about 150-200 people protest at a DAPL worksite in North Dakota.

Watch below as Stein tags a bulldozer with the words, "I approve this message":

But whereas Stein has been clear in her opposition to DAPL (as has former presidential candidate Bernie Sanders), Obama and Clinton have been absent—even as resistance has grown to include Indigenous people from across the U.S. and activists face increasingly severe crackdowns.

Three weeks ago, journalist and Oglala Lakota Nation citizen Simon Moya-Smith called on Clinton to weigh in, writing:

[B]ack in February, the Clinton camp posted to its website the candidate's policy platform for Native Americans. In it, Clinton declares that she "will continue to stand for Tribal sovereignty and in support of Tribal resources and sacred sites." Earlier this year, Clinton stumped in Indian country , vying for votes. But if she truly supports Native American sovereignty, and if she is sincere about honoring the treaties and protecting sacred sites, then she will take a stand against this ominous pipeline as well as the brazen violation of our treaty rights.

As for Obama, Moya-Smith wrote at the time,

two years ago, the President and first lady Michelle Obama visited the very same reservation being threatened by the pipeline today. They laughed and played with the children there at Standing Rock. They listened to the kids as they sang in ancient languages once outlawed by Christian invaders (popularly known as "settlers.") Will the Obamas now be silent at a time when those same children they so affectionately embraced need them most?

But on Tuesday, he noted that there has still been no word from Clinton or Obama.

(In the interim, an investigation revealed the more than two dozen major banks and financial institutions that are bankrolling the project—many of them Clinton and Obama donors.)

Meanwhile, climate group 350.org is circulating a petition urging Obama to "direct the U.S. Army Corps of Engineers to revoke the permits under 'Nationwide Permit 12' and stop the construction of the Dakota Access Pipeline once and for all."

Indeed, the organization said in an email to supporters, "President Obama could step in any time and say 'no' to this whole thing—like he did for Keystone XL."

"We know that to defeat a pipeline, it takes a movement of people from all corners of the nation," 350 wrote in its call to action. "This is Keystone all over again. And like Keystone, we can stop this pipeline through massive public pressure on the Obama administration to protect the land, water, and climate."

This echoes an open letter (pdf) sent last week from 350 and other environmental groups to Obama, which described DAPL as "yet another example of an oil pipeline project being permitted without adequate public engagement or sufficient environmental review" and called for the president to intervene.

Meanwhile, similar demands rang out on social media:

Hillary Clinton says she's committed to supporting Indian country. The #DAPL protest is her chance to prove it. https://t.co/N8Lo20vkNi — Maria Morrissey (@mamaria33) September 6, 2016

Because the backers behind the DAPL, Goldman Sachs et al, have purchased Hillary Clinton. https://t.co/MrrHPNsDJA — Ikka (@IsicaLynn) September 4, 2016

hey #Obama yr silence is deafening the #DAPL issue tip of iceberg or do U prefer 2 protect #CorruptDNC financiers? pic.twitter.com/AjRwrOQrJw — Tod Moore (@TodMoore3) September 7, 2016

What kind of leadership does it show when the "top" 2 candidates 4 POTUS will not speak up 4 Native people & neither will Obama. #NoDAPL — Tonya Beltre (@grnigrl76) September 7, 2016

Indeed, as environmentalist and 350.org co-founder Bill McKibben wrote in a piece published Tuesday in the New Yorker, the silence from politicians is deafening.

"Young people on the [Standing Rock Sioux] reservation organized a run across the country this summer to deliver more than a hundred thousand petition signatures to the President asking him to stop the pipeline," McKibben wrote. "They weren't received at the White House—disappointing, since Obama had actually visited the reservation in 2014. 'My Administration is determined to partner with tribes,' he told them then, but so far he's made no public statement on the Dakota Access pipeline."

"All of which is sad," McKibben continued, "because this case offers the U.S. government the chance to make at least small amends for some of the darkest parts of its official history—to demonstrate that it has absorbed at least a few small lessons from that past."