In the bombshell political trial of the century, JOHN EDWARDS' ex- speechwriter is trying to evade a subpoena to testify for her former boss.

Wendy Button who left the Edwards campaign and blogged for the Huffington Post about her frustrations with Edwards’ public denials about his extramarital affair with Rielle Hunter, is expected to be a key witness for the prosecution, the Raleigh News Observer reported.

Edwards legal whizzes issued a subpoena to Button similar to one that they issued to former loyalist Andrew Young, who pretended to be the love child’s father his former aide who later wrote a tell-all book confirming The ENQUIRER’s bombshell reports about hush-money payoff and alleged misuses of presidential campaign funds to buy a conspiracy of silence.

Edwards’  attorneys have requested for any correspondence and details of any calls she has had since 2009 with Young about the federal probe that led to the secret grand jury that culminated in Edwards’ arrest and indictment.

Edwards, a former cagey trial lawyer himself, who is said to have spearheaded his ex-mistress Hunter’s legal war with Young over possession of the couple’s sex tape, wants details of any communication she has had with others, including media outlets and other potential trial witnesses, about the facts of the case.

Edwards’ attorneys contend that Button has written a book that includes detailed information about the events that led to the criminal investigation.

In trying to sidestep the defense subpoena from Edwards’ lawyers, Button’s lawyer argued that the subpoena was overly broad, making it difficult for her to comply with the request before the trial begins.

Feds contend Edwards secretly obtained more than $900,000 from two wealthy contributors – 101 year old Listerine heiress Rachel “Bunny” Mellon and late Dallas money man Fred Baron to provide hush money payments for then-pregnant mistress Rielle Hunter as first detailed in an exhaustive ENQUIRER investigation.

Prosecutors argue the hundreds of thousands of dollars were campaign contributions that not only should have been reported, but also exceeded legal limits.

As The ENQUIRER reported last week jury selection has begun and insiders say that a favorable jury is the key to Edwards beating the charges.  But sources out of Chapel Hill, N.C. Edwards is pretty much of a pariah there – based on his mistreatment of his late wife Elizabeth who died after a long cancer battle while he did the horizontal mambo with new age temptress Hunter.

Hunter is expected to testify at the trial along with Andrew Young.