More than a dozen Democratic senators argued in a letter to President Trump on Monday that he doesn’t have the authority to order a preemptive strike on North Korea.

“Like many, we are deeply concerned about the potential consequences of a preemptive military strike on North Korea and the risks of miscalculation and retaliation,” the senators wrote.

“Without congressional authority, a preventative or preemptive U.S. military strike would lack either a constitutional basis or legal authority,” they added. 

We are sounding the alarm over South Korea Ambassador ​vacancy; Warning of significant risk of preemptive strike against North Korea. @SenatorCardin @SenJackReed @TimKaine @PattyMurray @ChrisCoons @SenWarren @SenMarkey @SenBrianSchatz @SenJeffMerkley @SenSanders @SenatorShaheen pic.twitter.com/gPMjieXN3s

— Martin Heinrich (@MartinHeinrich) February 5, 2018

Sen. Martin Heinrich (D-N.M.), who sits on the Senate Armed Services Committee, organized the letter. It was signed by 17 other Democrats and independents, including Sens. Ben Cardin (D-Md.), Tim Kaine (D-Va.), Bernie Sanders (I-Vt.), Kamala Harris (D-Calif.) and Elizabeth Warren (D-Mass.).

The Washington Post first reported the letter. 

The senators also expressed concerns over reports that Victor Cha would no longer be considered for the U.S. ambassador to South Korea after he objected to the possibility of a preemptive strike against North Korea.

The Trump administration is said to be considering options for a potential targeted military strike against North Korea, or a “bloody nose” strategy, which would be used to show Pyongyang the consequences of an all-out war.