American intelligence agencies must conduct a formal review of the damage to U.S. security caused by the disclosure of secrets on Hillary Clinton’s unsecure email server, according a to Republican senator.

Sen. Ben Sasse (R., Neb.) stated in a letter to Director of National Intelligence James Clapper that the failure to conduct a damage assessment risks discrediting U.S. intelligence agencies with charges of politicization or incompetence.

Sasse, a member of the Senate Homeland Security Committee, requested a formal damage assessment after a report in the Washington Free Beacon revealed that Clapper’s DNI office had declined to conduct the assessment—despite an intelligence directive requiring such inquiries in the wake of classified data compromises.

An FBI investigation into the Clinton email server found that highly classified data on CIA drone strikes against terrorists was improperly placed on the server and discussed in emails.

The FBI also said foreign intelligence services may have gained access to the emails sent and received by Clinton and several key aides between 2009 and 2013 when she was secretary of state, potentially increasing the damage from the information security failure.

"Brilliant and committed patriots work hard every day on our behalf in the Intelligence Community," Sasse told the Free Beacon. "We undermine that work if we shrug at the possible implications of these unauthorized disclosures."

Sasse said requesting the assessment is not a bid to drag the DNI into politics. "I’m interested in us securing our nation’s interests and secrets so that we can be safe," he said in an email.

In the letter, Sasse asked Clapper to explain why intelligence leaders apparently declined to conduct the damage assessment, based on an informal assessment that similar sensitive and classified data had been disclosed prior to compromise on the Clinton server. U.S. intelligence officials who opposed the damage assessment argued in internal discussions that the previous public disclosures about the drone strikes would make assessing the security damage difficult.

"Is this true?" the Nebraska Republican asked. "Are the ODNI and other intelligence agencies declining to conduct an assessment of the national security implications of unauthorized disclosures of sensitive and classified information by former Secretary Clinton’s use of a private, insecure email server? And, if so, what are the reasons for this decision?"

"In short, the lack of a formal assessment of these matters risks tarring your organization, and possibly the broader IC, with accusations of partisanship or incompetence," Sasse stated. "I believe both of these critiques are wrong; but, I request your timely answers to these questions in order to maintain this view."

Clinton, the Democratic presidential nominee, has come under fire for the email scandal. Clinton initially denied placing any classified information on the private server, and later modified the statement saying no information marked classified was sent and received on her email.

Both statements were shown to be false by FBI Director James Comey and a declassified report on the investigation.

Sasse noted in his letter that the refusal to conduct the assessment appears contrary to current intelligence policy.

A 2014 directive, Intelligence Community Directive-732, mandates that intelligence agencies conduct damage assessments after "actual or suspected unauthorized disclosure or compromise of classified national intelligence that may cause damage to U.S. national security."

"Even if information has been previously exposed, is it not prudent to understand the implications of this specific disclosure in terms of who gained access to the information and how they might leverage these insights?" Sasse asked.

A damage assessment would also be helpful in determining previous unauthorized disclosures and the overall impact on U.S. national security.

A DNI spokesman had no comment and said Clapper would respond to Sasse directly.

Russian intelligence is suspected in the major hacking of emails sent by the Democratic National Committee. The emails were disclosed on the Internet in what appears to be a covert Russian effort to influence the presidential election campaign in favor Republican nominee Donald Trump.

So far, leaked emails from Clinton’s server have not appeared online.

Wikileaks founder Julian Assange has said that additional leaks likely to embarrass American politicians are expected to be disclosed in the coming weeks.

The FBI and U.S. intelligence community reportedly are investigating covert attempts by Russian intelligence to influence the U.S. presidential election.

On Wednesday, Sen. John McCain (R., Ariz.), chairman of the Senate Armed Services Committee, asked the FBI to investigate whether Russian hackers sought to influence U.S. elections in Arizona by intruding on the state’s voter registration system.

McCain said FBI officials notified Arizona government officials that Russian hackers were behind attempts to breach the voter registration system, causing a nine-day shutdown of the website used for registration.

Russian hackers also appeared to break into the Illinois voter registration database, stealing some 200,000 voter records.

"Clearly, Russia is using cyber capabilities to undermine American national interests at every turn, and it appears that our democracy could be the next target," McCain stated in the Sept. 14 letter to FBI Director Comey.

"While these incidents reportedly involve the actual or attempted theft of data, rather than actions capable of manipulating the results of the elections, they are no less serious," he said. "In the hands of a sophisticated adversary, such data could be wielded as a weapon that could seriously undermine public trust in the election system and the legitimacy of our government."

U.S. Cyber Command chief Adm. Mike Rogers told a Senate hearing this week that Russian hacking is a serious concern.

"This is an ongoing investigation and in a public, unclassified forum, I'm not going to be able to provide you specifics as to what our current assessment is," Rogers said.

"I will say this that it continues to be an issue of great focus, both for the foreign intelligence community, attempting to generate insights into what foreign nations are doing in this area," he added.

The investigation into the Russian hacking includes officials from the FBI, Department of Homeland Security, Director of National Intelligence, and National Security Agency.