A majority of Americans oppose sending U.S. troops to defend Israel if it's attacked by a neighboring country, according to a poll released Tuesday. 

The Chicago Council on Global Affairs (CCGA) poll found that 55 percent of Americans oppose such military support of Israel while just 41 percent favor it, marking a shift from previous iterations of the poll over the last decade in which support for the U.S. defense of Israel was just above 50 percent. 

The poll comes as Israel braces for retaliatory attacks following the assassinations last week of Hamas leader Ismail Haniyeh in Tehran and Hezbollah commander Fuad Shukr in Beirut.

The U.S. has moved additional forces into the region to support Israel as diplomats try to deescalate tensions and prevent an all-out war in the Middle East. The poll was conducted June 21 to July 1 and doesn't account for these developments. 

The reasons for declining U.S. support for defending Israel aren't explored in the poll, but CCGA author Dina Smelt suggested that "the unrelenting Israeli attacks against Gaza have likely dampened American willingness to defend Israel," and critics of Israel's assault on Gaza drew similar conclusions.

"Nothing seems to undermine Americans' support for Israel more than Israel's own policies," Trita Parsi, executive vice president of the Quincy Institute for Responsible Statecraft, wrote on social media in response to the poll. 

CCGA's findings fit with other polling this year that shows decreasing American support for Israel, which has laid siege to the Gaza Strip for the last 10 months, killing nearly 40,000 Palestinians, according to the Gaza health ministry, and destroying a large proportion of the enclave's buildings.

The siege began after Hamas and affiliated militant groups massacred more than 1,100 Israelis on Oct. 7. [The Israeli daily Haaretz has reported that the IDF killed an unknown number of Israelis that day rather than allowing them to become hostages.]