Technology leaders such as Apple CEO Tim Cook and Salesforce CEO Marc Benioff recently signed an open letter, addressed to U.S. Homeland Security Secretary Kirstjen Nielsen, that argues against changes in immigration and H-1B policy. You can find the full text of the letter here, released by Business Roundtable, an association of the CEOs of leading U.S. companies. It kicks off with a familiar argument: “Changes in immigration policy… are causing considerable anxiety for many thousands of our employees while threatening to disrupt company operations.” From there, it breaks its criticism of U.S. Citizenship and Immigration Services (USCIS) into four parts:

Inconsistent Immigration Decisions

The letter attacks the recent USCIS decision to potentially reject applications and petitions without asking for either a Request for Evidence (RFE) or Notice of Intent to Deny (NOID): “Now, any adjudicator can disagree with multiple prior approvals without explanation.”

Uncertainty About Required Information

“Companies now do not know whether a work visa petition that was approved last month will be approved when the company submits the identical application to extend the employee’s status,” the letter continues. “This challenge is particularly acute for companies that hire H-1B professional workers where the government has narrowed eligibility criteria without issuing guidance to adjudicators or the public.”

Revoked Status for Spouses

The letter also criticizes the Trump administration’s decision to ban the spouses of H-1B visa holders from obtaining the H-4 visas that would allow them to find and hold jobs in the United States: “Other countries allow these valuable professionals to work, so revoking their U.S. work authorization will likely cause high-skilled immigrants to take their skills to competitors outside the United States.”

Commencement of Removal Proceedings

Under new policy, USCIS may deport certain workers whose applications are denied. “Our employees are concerned that they will face removal proceedings even if they have complied with immigration laws and intend to promptly depart the country,” the letter states.

Policy Battles

When President Trump took office, some pundits assumed that his administration would move quickly to reform the H-1B program, perhaps by radically curtailing the number of available visas. However, the administration’s changes have largely been incremental, such as giving USCIS more leeway for rejections. And even as USCIS has tightened some policy aspects, the number of H-1B petitions and approvals has only continued to rise. The National Foundation for American Policy (NFAP), a Virginia-based policy research group, found that companies such as Amazon, Facebook, and Google enjoyed double-digit increases in the number of approved H-1B visa petitions between 2016 and 2017. Based on this letter, though, it’s clear that some of tech’s most prominent CEOs are concerned about the government’s more recent policy changes. The big question is whether their criticisms can actually sway future policy.