I know nothing about law, so I have this question. If I am subpoenaed and don't show, I get arrested. How can Trump staff and former staff seemingly ignore a subpoena? Why would John Bolton, if subpoenaed, have a choice on whether or not to appear?
NPR did a good piece on this the other day. Basically the congressional Sargent at arms used to go and apprehend people violating their subpoenas but it often got messy and complicated so decades ago they back off forceful enforcement and started taking people to court. However court systems are slower and slower and now it often takes a court longer to decide on the validity of the subpoena than the subpoena is valid. Apparently all subpoenas expire with each congress so when a new congress is elected in 2020 the subpoenas have to be reissued and therefore retried in the court system. The expert on NPR, I think it was Fresh Air, asserted that the Democrats probably feel like they ready have enough evidence to impeach and don’t need these witnesses and they they could also add obstruction charges to the impeachment articles if they want to.