CHICAGO (CBS) — On the eve on the next GOP presidential debate, Donald Trump is doubling down and playing the liar card against rival Ted Cruz.

Saturday night’s debate in South Carolina (8 p.m., Chicago time on CBS 2) could get heated, if social media is any indication.

This morning, Trump mocked Cruz’s evangelical credentials.

Earlier, he questioned whether Cruz is not only a liar, but crazy.

Then there is lying AND accusations of dirty tricks

Trump was referring to rumors, generated by Cruz aides on the night of the Iowa caucuses, that Ben Carson was dropping out of race and urging Carson’s backers to support Cruz.

Yesterday, Cruz retweeted a polling story that showed how he, and not Trump, could beat Hillary Clinton in the general election.

Also yesterday, a tweet with an attack ad against Trump

Saturday night could be quite interesting.