Regardless of whether Iran plotted and ordered the massive Hamas attack against Israel over the weekend, Tehran’s backing and support for the Palestinian militant group sends a clear and defiant message to Washington.

The U.S. has yet to confirm a direct involvement from Tehran in the operation, but officials acknowledge Iranians are indirectly complicit in training, funding and supporting Hamas.

The Hamas invasion, the worst attack on Israel in 50 years, shows Tehran is increasingly willing to damage U.S. allies and, in effect, try to weaken American influence through proxy groups. It comes as Iran’s influence as a regional power appears on the rise.

Jonathan Spyer, the director of research at the Middle East Forum, said Iran seeks to defeat Israel with a strategy of “death by a thousand cuts.”

“They intend to reduce the morale of Israelis, to cause Israelis to lose faith in their institutions, to cause Israelis to quit Israel,” said Spyer. “That’s the reason why they’re backing Hamas. That’s the reason why they created Hezbollah. They intend to try to surround Israel with what we would call hybrid military forces.”

Iran has denied any role in the brutal surprise attack by Hamas but has welcomed the news, reportedly with celebrations of what Iranians are calling a Palestinian victory.

Both Hamas and Iran have publicly acknowledged a strategic partnership. They hold separate goals in the decades-long conflict with Jerusalem, but those aims appear to have aligned during the early Saturday attack, which has left hundreds dead in Israel and fighting still flaring up in the south near Gaza.

Iran has for years been fighting a shadow war against Israel through proxy groups, such as Hezbollah in Lebanon, Hamas and others. Tehran considers Israel an American client state, hostile to Muslims.

The weekend attack also came as Iran seeks to scuttle Israeli standing in the Middle East and restrict American influence by separating its most prominent allies: Israel and Saudi Arabia.

As Israel and Saudi Arabia have worked to normalize relations, Iranian Supreme Leader Ayatollah Ali Khamenei in early October leveled a sharp warning.

“The position of the Islamic Republic is that countries that make the gamble of normalization with Israel will lose,” he said, according to Iranian state media. “They are betting on a losing horse.”

Khamenei also said in those remarks that, “Today, the Palestinian movement is more active than ever.”

Efforts to normalize relations between Saudi Arabia and Israel, which had already been difficult, will likely face a major setback after the violence, said Asher Kaufman, professor of history and peace studies at the University of Notre Dame.

“I don’t think Saudi Arabia is able to work on normalizing relations with Israel so long as the war in Gaza takes place,” he said. “It might repair [relations] and resume this possibility after this war is over, but not now. I don’t see it happening now.”

Hamas, which has controlled the Gaza Strip since 2007, has suffered from corruption and domestic turmoil as relations with Israel have worsened with the far-right government of Israeli Prime Minister Benjamin Netanyahu, which has expanded settlements into the Israeli-occupied West Bank and cracked down against militant groups.

But over the past two years, Hamas largely fell under the radar, with speculation that it was focusing on the economy, while other Palestinian groups, such as the Islamic Jihad, have battled Israel with rocket attacks.

The surprise invasion, which saw Palestinians paragliding over a usually secure Israeli border and rolling through with bulldozers and motorcycles, came as Israel has been divided internally over Netanyahu’s political reforms.

Amid Israel’s domestic strife, Hamas wanted to display strength and put the Palestinian movement back on the international stage, said Matthew Levitt, the director of counterterrorism and intelligence at the Washington Institute for Far East Policy.

“They saw an Israel they believed was weak, and they wanted to do something that would demonstrate that Israel is not 10 feet tall,” he said. “It was showing that it could happen, that Israel is not invincible and that you can’t ignore Hamas.”

Hamas could not have accomplished any of last weekend’s attacks without Iran, a nation to which it has historic ties. That relationship actually fell apart amid tensions in Syria but has strengthened again in the past few years, and Iranian officials have provided militants with significant training and resources.

The Wall Street Journal reported Sunday that Iranian security officials plotted out the invasion and gave Hamas the thumbs up to attack. Both the U.S. and Israel have yet to make that declaration and have signaled there is no evidence to make the claim, while analysts have said it remains an open question.

Still, the attack underscores how deeply the U.S. has failed to rein in Iran, despite attempts to reach a mutual agreement through the revival of a deal to restrict Iranian nuclear ambitions. And just last month, the U.S. approved a deal to unfreeze $6 billion of funds in South Korea from Iranian oil sales for the release of five American prisoners.

On Capitol Hill and the campaign trail, Republican lawmakers are hammering the Biden administration for releasing the funds just weeks before the Hamas attack, despite no established link between the two events.

“President Joe Biden’s kowtowing for the last two and a half years to the mullahs in Iran, lifting sanctions, begging them to get back in the Iran nuclear deal, and then paying $6 billion in a ransom for hostages, I think, set the conditions for this unprecedented terrorist attack by Hamas against Israel,” said former Vice President Mike Pence, who is running for the White House in 2024.

No White House has found the right formula for dealing with Iran.

Sanam Vakil, a professor at Johns Hopkins University and the director of the Middle East and North Africa Program at Chatham House, said Iran has “been a destabilizing actor in the region for decades now.”

“No U.S. president has developed a policy to manage and contain Iran’s regional role,” she said. “A whole new approach, a whole new Iran strategy is urgently needed.”

Following the attack, the West is increasingly concerned with whether America’s longtime influence in the Middle East is waning.

Alarm bells rang earlier this year when China helped restore diplomatic ties between Iran and Saudi Arabia — a deal in which the U.S. played no part.

Regional nations like Iran see the U.S. as losing power in the Middle East, and if Israel were to be weakened by the conflict, that could threaten Washington’s influence even more.

Spyer, from the Middle East Forum, said Tehran is demonstrating that “Iranian power is on the way up.”

“They regard themselves as the rising power,” he said, and view the “United States as the setting sun, the power which is declining and departing the Middle East.”