WASHINGTON — Israel's ban on two Muslim members of Congress has provided an opportunity for progressive pro-Palestinian groups in America to highlight the chumminess between Donald Trump and Benjamin Netanyahu — and to try to influence the stance of Democratic presidential candidates on the campaign trail.

"This is a watershed moment on how Democrats will engage with Israel's increasing moves toward the far-right under Netanyahu," said Waleed Shahid, a spokesman for Justice Democrats, which is closely aligned with Reps. Ilhan Omar and Rashida Tlaib, who were both barred from entering Israel on Thursday.

The two lawmakers are among the most prominent to support the Boycott, Divest and Sanctions movement (BDS) against Israel, which Israel considers an attack on its right to exist. Under Israeli law, its backers can be prohibited from entering the country.

The House of Representatives voted to condemn the BDS movement in a whopping 398-17 vote last month.

Pro-Palestinian activists said they saw Israel's decision, under public pressure from President Donald Trump, to bar two members of "the squad" of freshman progressives as a chance to push the party toward the left in the midst of the 2020 campaign.

While many Democrats condemned Israel's move on Thursday to keep the lawmakers out and Trump's support for it, activists want them to go further.

"What we're trying to do is make clear that what the next U.S. president needs to do in order to achieve freedom and dignity for all Israelis and Palestinians is to put direct pressure on the Israeli government to end the occupation," Yonah Lieberman, a founder of IfNotNow, a left-wing Jewish grassroots organization, told NBC News.

The close alliance between Trump and Netanyahu, he said, is "opening up space politically" for groups like his to make the case that Democrats should feel more confident in criticizing Israel's actions.

On Thursday, the group put out a petition demanding Democrats in Congress refuse to travel to Israel unless Omar and Tlaib are allowed in. "Trump and Bibi have made the sides clear: advocates for human rights and equality on one, and those cooperating with a strategy to roll back the foundations of democracy on the other," it said.

IfNotNow has started dispatching supporters in recent weeks to 2020 Democratic campaign events to grill candidates on whether they'd call Israel's presence in the West Bank and Gaza an "occupation" and take steps to end it.

The group has a neutral stance on BDS, but counts Tlaib and Omar as allies.

Trump has used inflammatory language to denounce Omar and Tlaib and to portray Democrats as hostile to Israel, part of the president's broader campaign to portray the party as captured by the far-left and sow doubts among Jewish voters, who have historically supported Democrats.

But Lieberman believes that Trump's condemnations of immigrants and Muslims, along with concerns over the rise of violent hate groups, are driving a further wedge between Netanyahu's government and American Jews, 79 percent of whom voted Democratic in the midterms, according to exit polls.

Progressives, he said, would take note that Israel is "closing their doors to popular progressive champions who are leading the fight against white nationalism" and who Lieberman described as "some of the strongest allies of the Jewish community."

Democratic presidential candidates recently have grown bolder about criticizing Netanyahu.

Beto O'Rourke called him "racist" in Iowa. Sen. Elizabeth Warren, whose campaign staff includes IfNotNow co-founder Max Berger, accused the Israeli prime minister of "embracing right-wing extremism" and "manipulating a free press, accepting bribes, and trading government favors" after he was hit with accusations of corruption.

IfNotNow is still hoping to push the White House contenders toward more concrete action, for example tying U.S. aid to changes in Israeli policies.

That approach got a boost this week when Sen. Bernie Sanders, I-Vt., told an activist with the group in New Hampshire that he would "leverage that money to end some of the racism that we have recently seen in Israel," although most candidates are reluctant to go that far. If Not Now issued a statement criticizing Warren for pledging to push Israel to do more to negotiate with the Palestinians without offering specifics.

It was clear on Thursday that many traditional supporters of Israel, both inside and outside the Democratic Party, were anxious about how the increasing bond between Trump and Netanyahu was inflaming the debate at home.

Rabbi Rick Jacobs, head of the Union for Reform Judaism, issued a statement decrying the decision and warning it could create new vulnerabilities for Israel supporters. "The consequences of their actions today will, I fear, reverberate for years both in undermining Israeli democracy and in making Israel a 'wedge issue' in American politics," he said.

Opponents of the decision to block Omar and Tlaib included AIPAC, the pro-Israel lobbying organization that Omar once accused of buying off lawmakers, prompting accusations from her own party leaders that she had invoked anti-Semitic tropes. Omar later apologized.

House Majority Leader Steny Hoyer, D-Md., who visited Israel along with dozens of lawmakers in both parties this month, publicly defended Netanyahu when he was there against charges of racism, but on Thursday called the ban "unwarranted and self-destructive."

Michael Oren, a former Israeli ambassador to the United States under Netanyahu, said on MSNBC that he worried the ban would make life harder for Democratic allies who had "visited Israel this summer to come out and defend us against the anti-Israel wing of the progressives."

"The question is not whether Israel has the right“ to bar Omar and Tlaib, he said. "The question is whether by exercising that right is Israel being smart."