President Trump with President Abdel Fatah al-Sissi of Egypt in the Oval Office in April 2017. (Evan Vucci/AP)

REEM MOHAMED DESOUKY and her 13-year-old son Moustafa stepped off a plane in Cairo last month to visit relatives in the city. But Ms. Desouky, who is a dual U.S.-Egyptian national, never made it to her family. After being detained and interrogated at the airport, the art teacher from Pennsylvania was jailed for allegedly criticizing the Egyptian government on Facebook. Authorities in Egypt have not revealed which posts led to her arrest.

Last week, Ms. Desouky’s brother and son went to visit her at Qanatir Prison in Cairo, where she is being held. Moustafa was not allowed in, and his uncle never reemerged. The boy remains under the care of family members in Cairo, unsure of what to do when school starts back home at the end of August. It shows an unusual level of spitefulness to seize a man who comes to see his sister in prison. Now, all her relatives fear even trying to visit her.

Ms. Desouky is one of many individuals imprisoned in Egypt for what many governments would accept as normal, healthy, peaceful criticism. Her story, once again, reveals the rampant erosion of freedom under the regime of President Abdel Fatah al-Sissi, whom President Trump has enthusiastically embraced.

Egypt’s crackdown has intensified since 2017, perhaps fueled by Mr. Trump’s indication that the protection of human rights in the Middle East is of no concern to him. In 2018, the Egyptian parliament passed a law granting extensive censorship powers to the government, muzzling everything from critical journalism to social media posts. Apparently no one is safe from the arbitrary arrests, abuse and even extrajudicial killings carried out by Mr. Sissi’s regime.

According to Human Rights Watch, Ms. Desouky is one of three U.S. citizens currently detained on politically motivated charges, and without due process, by Egyptian authorities. Michael Harker, a spokesman at the U.S. Embassy in Cairo, wrote in an email to The Post that “we are aware of Ms. Desouky’s case and are providing consular services at this time.” Ms. Desouky’s family and her lawyer told The Post that no U.S. consular officer has visited her in prison.

The White House, which sporadically has shown interest in freeing similarly held Americans in the past, should step up. Last year, Ahmed Etiwy was released after nearly five years of imprisonment for a protest he did not attend when Vice President Pence put pressure on Mr. Sissi’s regime. In 2017, humanitarian aid worker Aya Hijazi was freed after a prodding from Mr. Trump. The administration should not forget Ms. Desouky and her lawless detention.