AWS Directory Service supports smart card authentication in AWS GovCloud (US-East) Region

Starting today, you can use Common Access Card (CAC) and Personal Identity Verification (PIV) smart cards to authenticate users into Amazon WorkSpaces through your self-managed Active Directory (AD) and AWS Directory Service AD Connector in the AWS GovCloud (US-East) Region. Additionally, you can now use the AWS Management Console to configure smart card authentication with AWS Directory Service. 

Source:: Amazon AWS