WASHINGTON -- One of the architects of unprecedented new legislation that would restrict U.S. arms sales to Saudi Arabia believes the Obama administration has repeatedly deflected questions about its ongoing support for Saudi actions in Yemen.

Rep. Ted Lieu (D-Calif.) said his frustration with the U.S. policy is one reason why he joined three other lawmakers to propose barring the sale of more American bombs and missiles to Saudi Arabia until the administration provides new guarantees on Saudi behavior.

That precondition means that the measure, introduced earlier this month, is an indictment of President Barack Obamas approach to the kingdom as much as it is one of Saudi wrongdoing.

In March 2015, Obama quietly approved a U.S. role in a Saudi-led military effort to restore Yemens internationally recognized government, which had lost its capital and much of the country to Iran-backed rebels. U.S. intelligence began to flow to the campaign and U.S. planes began refueling its jets, as Saudis and other Gulf Arabs deployed U.S. weaponry sold to them with the presidents permission.

Not long afterward, Lieu began to read the news of what the U.S. military was helping the Saudis and their allies do in Yemen -- dropping bombs that killed hundreds of civilians , including children , and bringing widespread destruction to one of the poorest countries in the Muslim world. The congressman said he contacted Obama administration officials, including Gen. Joseph Dunford , the newly appointed chairman of the Joint Chiefs of Staff, for answers to three broad questions:

• What is the U.S. national security interest in supporting the Saudi-led air coalition in Yemen?

• Why is this coalition dropping bombs on civilians nowhere near military targets?

• How is the U.S. going to stop that from happening?

The effort initially appeared to win results. "The administration gave me a briefing last year," Lieu told The Huffington Post in a recent interview. "After the briefing, I came out with the impression that things were going to get better."

But months later, Lieu had to write another letter to the secretaries of state and defense.

"Having served on active duty in the U.S. Air Force, and as a graduate of Air War College, I understand that in the fog of war no battle plan will be executed perfectly," the congressman wrote in a message dated March 2. "As I previously wrote to Gen. Dunford, however, the apparent indiscriminate airstrikes on civilian targets in Yemen seem to suggest that either the coalition is grossly negligent in its targeting or is intentionally targeting innocent civilians."

To Lieu, it looked like things had actually gotten worse since his initial complaints. The congressman is still waiting to hear back from the administration in response to his latest message.