A group of Democratic senators sent a letter demanding the Congressional Budget Office look into the cost of deploying National Guard troops to U.S. cities.

PORTLAND, Ore. — Oregon’s U.S. Sen. Jeff Merkley is leading an effort to demand the Congressional Budget Office investigate the cost of the Trump administration’s decision to deploy National Guard troops to cities across the U.S. 

Merkley and 10 other Democratic senators, including Oregon’s U.S. Sen. Ron Wyden, sent a letter to CBO Director Phillip Swagel on Monday. The senators are asking the CBO to analyze the costs of activating, deploying and compensating National Guard members, along with the cost to sustain and maintain the deployments.

“Deploying federalized National Guard units for domestic security operations marks a significant departure from long-standing practice. It also carries substantial cost implications that have not been publicly disclosed or formally justified to Congress,” the letter says, in part. “The American people deserve full transparency regarding how their tax dollars are being used, especially as it pertains to the deployment of military personnel for missions on U.S. soil without a declared emergency or state request.”

The senators argued in the letter that Congress must have a “clear understanding of both the immediate and long-term budgetary consequences of this policy.”

The letter comes as as U.S. District Court Judge Karin Immergut considers whether to lift her previous order temporarily blocking the deployment of all Guard troops to Portland. It also follows the U.S. 9th Circuit Court of Appeals’ decision on Friday, Oct. 24 to temporarily suspend its earlier ruling that would have allowed federal deployment of Oregon National Guard troops in Portland. The pause will remain in effect until 5 p.m. on Tuesday, Oct. 28, while the court decides whether to take another look at the case.

National Guard troops have been deployed to Los Angeles, Washington, D.C. and Memphis. Aside from Portland, the Trump administration has also pushed to send troops to Chicago, where they’ve been similarly blocked by federal court decisions.

The CBO is a nonpartisan federal agency that provides information to help the Congressional budget process, though it does not make policy recommendations.

Merkley is the ranking member of the Senate Budget Committee. Last week, he held a marathon 22-hour speech on the Senate floor where he condemned the Trump administration’s attempts to deploy National Guard troops to Portland.