Tl;Dr: US officials are shitting themselves because arrest warrants could undermine any attempts to negotiate a cease-fire, but more importantly, because if the ICC issues arrest warrants for Israeli politicians, they might turn around and do the same to US politicians. No, seriously. Straight from the article:

US House Speaker Mike Johnson slammed as “disgraceful” the ICC’s reported intention of issuing “baseless and illegitimate arrest warrants” for alleged war crimes against Prime Minister Benjamin Netanyahu, Defense Minister Yoav Gallant and IDF Chief of Staff Herzi Halevi.

“Such a lawless action by the ICC would directly undermine US national security interests,” Johnson said Monday. “If unchallenged by the Biden administration, the ICC could create and assume unprecedented power to issue arrest warrants against American political leaders, American diplomats, and American military personnel, thereby endangering our country’s sovereign authority.”