The Scottish Lib Dem leader made one of his most bitter attacks yet on nationalism as he suggested the SNP was attempting to claim that Scots had to back independence to be patriotic.
Mr Rennie, speaking at a meeting on voter attitudes, added there were no “unique Scottish values” – an idea he said the SNP promoted.
He said: “They [the SNP] are playing with identity. It’s a dangerous game to play.
“I’m not quite sure there are unique Scottish values. There are values that Scottish people have.
“They are trying to say we are different, but I don’t think we are uniquely different. To say that we all have to believe this or we are not Scottish is a dangerous game.
Mr Rennie went on to claim the SNP “try to keep a lid” on hostile nationalism, but attacked the party’s senior figures for failing to condemn the high-profile protest in Edinburgh this year against Ukip leader Nigel Farage.
Meanwhile, Scottish Secretary Michael Moore warned that the referendum debate would become increasingly bitter.
Mr Moore said: “It will get more heated as it goes on. I don’t want a definition of Scottishness that means you’d vote for independence.”
But SNP MSP Stuart McMillan, who sits on the Referendum (Scotland) Bill Committee, said: “Mr Rennie doesn’t seem to understand what the referendum is about – it’s about democracy, not identity. Independence is the broad, inclusive and positive choice for Scotland, in which all these identities can be reflected and celebrated.”