Sinn Féin's chief negotiator, Mr Martin McGuinness, told a republican rally in Belfast last night that they faced a huge challenge to withstand the "avalanche of propaganda" against them.
The most immediate challenge was the local and expected Westminster elections in May and, whenever "others come to their senses", to rebuild the peace process.
Mr McGuinness, echoing recent comments by Sinn Féin president Mr Gerry Adams, told the rally of 600 people in the Hilton Hotel that "no republican worthy of the name" can be involved with criminality.
"If any are, we are absolutely determined to see that they are out of our ranks. We are not involved in criminality, and we will not tolerate under any circumstances such behaviour. Our opponents know that in their heart and soul, but some can barely disguise their glee at the recent turn of events."
He said that following Garda raids and arrests last week, a media "kangaroo court" immediately went into operation even though only one person was charged, and of the several arrested only one was a Sinn Féin member.
He described Mr McDowell as the "so-called Minister for Justice, a minister that I describe as a minister for smear, for allegations and for by-passing justice, challenging my credentials, Gerry Adams's credentials and Martin Ferris's credentials".
He said Mr McDowell's comments naming him, Mr Adams and Mr Ferris as members of the IRA army council were a "grossly disgraceful abuse".