March 11 (Reuters) - A standoff erupted between the U.S.

Department of Defense and Anthropic in January after the AI lab

refused to loosen safety guardrails on its systems, prompting

the Pentagon to label it a 'supply-chain risk,' and putting the

company's government contracts in jeopardy.

The Claude maker's executives warned that the designation,

which they view as retaliation for opposing the use of their

technology in autonomous weapons and domestic surveillance,

could slash their 2026 revenue by billions of dollars.

Legal experts suggest the government's case may be

undermined by a mismatch between the law invoked and Anthropic's

conduct, internal contradictions in the Pentagon's behavior and

evidence that its decision may have been driven by animus rather

than security.

Here is a timeline of the ongoing conflict:

January 29 The Pentagon and Anthropic

clash over eliminating

safeguards that could allow

the government to use its

technology to target weapons

autonomously and conduct

U.S. domestic surveillance

February 11 The Pentagon pushes AI

companies, including

Anthropic, to make their AI

tools available in

classified settings without

many of the standard

restrictions that the

companies apply to other

users

February 14 The Pentagon considers

ending its ties with

Anthropic over the AI lab's

insistence on keeping some

limits on how the U.S.

military uses its models

February 23 U.S. Defense Secretary Pete

Hegseth summons Anthropic

CEO Dario Amodei to the

Pentagon for talks on the

military use of Claude

February 24 The Pentagon asks Anthropic

to get on board, or risk

consequences, including

being labeled a supply-chain

risk

February 25 The Pentagon asks defense

contractors, including

Boeing and Lockheed

Martin , to assess

their reliance on Anthropic

February 26 Pentagon spokesperson Sean

Parnell asks Anthropic to

allow the Pentagon to use

its technology for all

lawful purposes, giving the

company until 5:01 p.m. ET

on February 27 to decide

February 26 Anthropic says it will not

accede to the Pentagon's

request to eliminate

safeguards from its AI

systems

February 27 U.S. President Donald Trump

directs every federal agency

to immediately cease all use

of Anthropic's technology

February 27 Hegseth directs the U.S. DoD

to designate Anthropic a

"supply-chain risk to

national security"

February 27 Anthropic says it will

challenge in court the

Pentagon's decision

February 27 OpenAI announces deal to

deploy technology in the

DoD's classified network

February 28 OpenAI says its latest

agreement with the Pentagon

includes three red lines:

its technology cannot be

used for mass domestic

surveillance, to direct

autonomous weapons systems

or for any high-stakes

automated decisions

March 2 The U.S. Departments of

State, Treasury and Health

and Human Services move to

cease using Anthropic's

Claude

March 3 Lockheed Martin pledges to

follow the DoD's direction,

signaling a likely exodus of

defense contractors removing

Anthropic's tools from their

supply chains to protect

their federal contracts,

legal experts say

March 4 U.S. Treasury Secretary

Scott Bessent tells CNBC

that the agency will remove

Anthropic from its

government systems within

days

March 4 Big tech industry group

pushes to de-escalate the

clash, saying a supply-chain

risk designation creates

uncertainty for companies

and could threaten the

military's access to the

best products and services

March 5 The U.S. DoD formally

designates Anthropic as a

supply-chain risk

March 6 Amazon says it is helping

customers transition DoD

workloads to alternative

models on its cloud, while

customers and partners

could continue using Claude

for all non-Pentagon

workloads

March 6 The U.S. General Services

Administration draws up

strict rules for civilian

artificial-intelligence

contracts and terminates

Anthropic's OneGov deal,

which made Claude available

to the federal government

March 9 Anthropic sues to block the

Pentagon from placing it on

a national security

blacklist, saying the

designation is unlawful and

violates its free speech and

due process rights

March 9 Anthropic executives say the

U.S. government's

blacklisting of the AI firm

could cut its 2026 revenue

by multiple billions of

dollars and cause

reputational harm

March 10 Microsoft files a

brief backing Anthropic's

lawsuit, saying the DoD

designation directly affects

it and that a temporary

restraining order is needed

to avoid costly supplier

disruptions and rushed

rebuilding of products that

depend on Anthropic

(Reporting by Anhata Rooprai in Bengaluru; Editing by Arun

Koyyur)