The United States is heading down a road that will be difficult to reverse, according to Cardinal Blase Cupich of Chicago.

On Feb. 28, the United States and Israel launched coordinated strikes on several sites in Iran. More than 1,000 Iranians have been killed so far in the conflict, along with at least 20 members of the U.S. and Israeli militaries.

Iranian state television said the country’s leaders are calling for the “shedding of blood” from Israelis and U.S. President Donald Trump.

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U.S. Secretary of Defense Peter Hegseth said additional forces will soon arrive in the Middle East and that the United States “will take all the time we need to make sure that we succeed.”

Cupich told Vatican News that when the United States begins to take a military approach to disputes, “we are going down a road that’s very hard to come back from.”

“We see that more and more in this particular moment. So, I think people are afraid. They have no idea how this is going to end, and things can get out of control very quickly,” he said.

The cardinal cited the history of the 20^th century as an example.

“Let’s remember the First World War started with an assassination of the Archduke in Sarajevo,” he said.

“Then it blew up into a great war when Franz Josef declared war on behalf of the Austrian Empire. He thought it would be a very quick solution to a problem. Well, it turned out to be years of terrible conflict in which millions of people were killed. So, once you open that door, it’s very hard to close it,” Cupich told Vatican News.

The cardinal also said the idea that the attack on Iran had a legitimate purpose was “very questionable” since there is no immediate threat from the Middle East nation.

“We have been told that the nuclear capabilities of Iran…have been neutralized by a bombing that took place months ago,” he told the news agency.

“And so, the sovereignty of a nation is very important. We have the same issue with regard to the war in Ukraine. When in fact that principle of the sovereignty of a nation is violated, then we can make any excuse to go ahead and wage war,” Cupich added, noting that has been the international consensus since the end of World War II.

RELATED: Pope warns against ‘spiral of violence’ as US attacks Iran

The cardinal also said Pope Leo XIV, in his comments on the conflict, is recalling the principles by which nations have agreed to deal with tensions and conflicts.

“In fact, there is a threat that we are losing that consensus,” Cupich said.

In his Angelus appeal on Sunday, Pope Leo said he was following “with deep concern what is happening in the Middle East and in Iran in these dramatic hours.”

“Stability and peace are not built with mutual threats nor with weapons, which sow destruction, pain, and death, but only with a reasonable, authentic and responsible dialogue,” the pontiff said.

Leo warned that the situation in Iran risked escalating into “a tragedy of enormous proportions” and urged all parties involved “to assume the moral responsibility of halting the spiral of violence before it becomes an unbridgeable chasm.”

In his interview with Vatican News, Cupich praised the pontiff.

“I think he is speaking on behalf of many people who are worried about what happens when that consensus breaks down,” he said.