What I found interesting is that the federal courts, except for the 7th Circuit en banc, thought the confession was coerced by a 4-3 decision.
Here's the 7th Circuit's en banc decision:
http://media.ca7.uscourts.gov/cgi-b...C:16-3397:J:Hamilton:aut:T:fnOp:N:2074184:S:0
The analysis starts on page 26.
I'm not versed on the AEDPA at all (which is what coerced confessions are reviewed under). In fact, I don't like it because it deprives the courts in fairly reviewing the confession under the normal appellate standards (de novo for issues of law, substantial evidence for issues of fact). It appears that the AEDPA requires that the federal court look to the last "reasoned" state court decision and then determine if that state court decision was unreasonable, rather than apply the law to the found facts.
In other words, the federal courts are forced to give the state courts deference in their decision. It reads like it's almost an arbitrary and capricious standard--if we were in administrative law. And while there's an argument for A&C in admin law, I don't think there's a compelling reason for deference in criminal law when federal constitutional questions are involved (state constitutional questions, yes, because state supreme courts decide their own state constitutional questions and the federal courts must bow to those decisions and interpretations).
While I am sympathetic to the federal courts having to address the issue of the abuse of the writ of habeas corpus in the post petition context, I think the AEDPA goes too far. Federal courts are the best courts for interpreting and applying the federal constitution.