Several artists from the Middle East couldn’t attend their own MoMA PS1 show due to the travel ban and other diplomatic issues.

MoMA PS1’s newest show, “Theater of Operations: The Gulf Wars, 1991–2011,” explores the legacy of U.S. interventions in the Middle East and features work by dozens of artists from the region. But several of the artists in the exhibition were unable to attend its opening last weekend due to U.S. President Donald Trump’s travel ban.

According to artnet News, at least four artists who tried to get travel visas were denied due to the travel ban or other diplomatic issues. And other artists didn’t even try to get visas, knowing that they would not be allowed entry. One artist was questioned when they arrived to the United States, but was still able to come to the opening. Among the artists who were unable to make the opening were the Iraqi artists Ali Eyal and Afifa Aleiby.

Ruba Katrib, one of the show’s curators, told artnet News:

More would have wanted to come, but knew there was no way. Artwork is able to travel more easily in some cases than the artists themselves.

The travel ban has been in place since December 2017, and was instituted by a presidential order, though the U.S. Supreme Court affirmed it in a 5–4 decision. The ban indefinitely suspends immigrant and non-immigrant visa applications from Libya, Iran, Somalia, Syria, Yemen, North Korea, and Venezuela.

In addition to the artists based in Iraq and its diasporas, “Theater of Operations” includes Western artists responding to the conflicts. One such artist, Phil Collins, withdrew his video work baghdad screentests (2002) from “Theater of Operations” to protest Museum of Modern Art board trustee Larry Fink’s investments in private prison companies, according to a Hyperallergic report. Collins is a England-born and Berlin-based artist, so he was not subject to the travel ban.