And Trump's attorney is not the only one whining that Cohen is a liar. Republican politicians, especially those committed to Trump and his lies, are doing the same.
There is more than a little bit of hypocrisy in their claims though.
Michael Cohen is a liar. They are right about that. But what did he lie about? He lied when questioned by the government about Trump's secret payments to keep the tryst with Stormy Daniels from becoming public knowledge before the 2016 election.
He lied to protect Donald Trump. The Republican politicians didn't have a problem with those lies. After all, many of them also regularly lie to protect Trump.
It was not until Cohen was convicted and punished with imprisonment that his story changed. After serving his sentence and promising to testify truthfully that the GOP politicians began to attack Cohen for being a liar. It's not the lies that bothered them. It's the truth that he's now telling.
For today's Republicans, telling the truth about Trump is a sin. One is supposed to go to the grave telling lies to cover for Trump. Evidently, truth is no longer a Republican value.