The specter of an Israeli invasion of Rafah has sparked a resurgent debate among Democrats in Washington over whether aid to the country should be tied to human rights conditions.

Why it matters: President Biden and Israeli Prime Minister Benjamin Netanyahu are increasingly at odds over the operation, which U.S. officials and lawmakers fear will be a human rights calamity

• Netanyahu has framed it as imperative for Israeli security, despite the more than one million Palestinian civilians sheltering in Rafah.

Driving the news: A group of progressive senators led by Sen. Bernie Sanders (I-Vt.) sent a letter to Biden calling for him to condition aid on the facilitation of humanitarian aid into Gaza.

• "We urge you to make it clear ... that failure to immediately and dramatically expand humanitarian access and facilitate safe aid deliveries throughout Gaza will lead to serious consequences," they wrote.
• The letter follows a call from a group of House Democrats last week for Biden to considering suspending aid if Israel invades Rafah.
• Both letters focus on a national security memo Biden signed last month requiring Israel to abide by international law in its use of U.S. weapons and allow humanitarian aid into Gaza.

Between the lines: Biden has in recent days signaled a break with Netanyahu's war strategy even as he affirms his support for Israel in its fight against Hamas.

• The Rafah operation — which Axios' Barak Ravid reports could take place as soon as April — would prompt the White House to consider setting conditions on military aid to Israel, according to Politico.

Yes, but: Some moderate pro-Israel House Democrats made clear to Axios they would oppose conditioning aid under any circumstances.

• "I'm not for conditioning aid. We don't condition aid now, we shouldn't condition aid," Rep. Debbie Wasserman Schultz (D-Fla.) told Axios.
• Rep. Kathy Manning (D-N.C.) said it is "critically important for Israel to make sure that Hamas can't come back" and that the U.S. should "continue to stand shoulder to shoulder with our democratic ally."
• "I would not support it," Rep. Tom Suozzi (D-N.Y.) said.
• "It shouldn't be done," said former House Majority Leader Steny Hoyer (D-Md.).

Zoom in: Even just the idea of narrow conditions — such as stipulating that U.S. weapons cannot be used in Rafah — has been met with strong pushback.

• "If you're going to take away smarter weapons and then you're going to leave them older, more dummy weapons, that's could lead to more loss of innocent Palestinian life," said Rep. Moskowitz (D-Fla.).
• Moskowitz added that it's "really dangerous" to condition aid, saying Biden has "been clear on that" and shouldn't do an "about-face."
• Wasserman Schultz said she is "confident the president has no plans or intentions of conditioning aid" and "certain the majority of Congress" would oppose doing so.

The other side: Several progressives told Axios that some kind of conditions would be necessary for them to lend support to a military assistance package to Israel.

• "Watching the devastation ... it's just such a terrible mess that I think recognizing that, from the White House level, will be significant and what people are looking for," said Rep. Mark Pocan (D-Wisc.).
• Rep. Alexandria Ocasio-Cortez (D-N.Y. ) suggested that narrow conditions wouldn't satisfy some on the left, citing a concern that "there's a lot of superficiality when it comes to U.S. policy" on Gaza.
• "Are these real conditions or are they going to be more aesthetic conditions? So, I welcome the conversation — let's make sure it's real," she said.