Republican presidential candidates continue to campaign in South Carolina as the primary is set for Saturday.

FOX's Eben Brown reports:

The former President has been the bullseye for attacks by Donald Trump against Jeb Bush, who says his brother doesn't have to be ashamed of anything:

(Bush) "And he served with honor. He served with distinction. Donald Trump criticizing my brother, castigating him, pushing him down, isn't gonna change anything."

Meanwhile, Marco Rubio has been fending off verbal and written tirades against him, challenging his political credentials:

(Rubio) "The Democrats think I should be a liberal because of where I come from, because my parents are immigrants, because my parents didn't make a lot of money. But I'm a conservative."

And the primary isn't until Saturday.

Eben Brown, FOX News.