Although they are both intelligent men, Laertes and Polonius are mere pawns in the play Hamlet.

I don't know how intelligent Polonius and Laertes are in
Shakespeare's Hamlet, but they certainly serve as
pawns.

Both men are used as pawns by King Claudius. 
Polonius is so intent on sucking up to Claudius and getting his approval that he happily
does whatever Claudius wants him to.  Polonius comes up with the idea that Hamlet is
acting as if he has lost control of himself because he has been rejected by Ophelia. 
The king sends him on a mission to see if this is actually the case.  Polonius doesn't
know it, but Claudius only cares about Hamlet's madness because he feels threatened by
Hamlet.  Claudius is afraid Hamlet is going to rebel and attempt to take the throne
back.  He gets Polonius to spy on Hamlet so he can keep an eye on Hamlet and figure out
if he's planning anything subversive.

Claudius uses Laertes
even more blatantly.  He gets Laertes to plan an underhanded murder of Hamlet.  Laertes
thinks Claudius is helping him because Hamlet killed Laertes's father, Polonius.  In
actuality, of course, Claudius is getting Laertes to help him eliminate a threat to the
throne.  Laertes is a dupe who plays right into Claudius's
hands.

Hamlet doesn't use Laertes as a pawn as Claudius
does, but he certainly abuses Polonius.  Sent to spy on Hamlet, Polonius is played by
Hamlet, taking the message back to Claudius that Hamlet is, indeed, suffering madness
because he's obsessed with Ophelia.  This is what Hamlet wants Polonius and Claudius to
conclude.  Hamlet is putting on an "antic disposition," pretending to be mad so Claudius
won't suspect that he is actually planning revenge.