Claudius is a brilliant tactician when it comes to getting people to do what he wants without them even realizing that they are being manipulated. This is very evident in Act 4, Scene 7. Earlier in the Act Laertes storms into the room and demands vengence on Claudius and Hamlet for the death of the his father. He is angry that Claudius didn't do something to keep Hamlet in check, especially since he is acting crazy. He vows vengence at all costs. It doesn't take but a short conversation for Claudius to calm Laertes down and pin all the fault on Hamlet, and excusing his own choices. When Ophelia comes into the room and has clearly lost her mind, Laertes in riled up again, but Claudius calms him down again.
At the start of Scene 7 he tells Laertesto "put me in your heart for friend." By strengthening the closeness of the relationship, it makes Laertes more easy to control. Claudius comes up with a rational reason why they must proceed with caution against Hamlet for the people of Denmark have "great love . . . [to] bear him, / Who, dipping all his faults in their affection." They are willing to forgive Hamlet anything because he is so well liked, so they must proceed with caution. After they learn that Hamlet has returned to Denmark, Claudius asks Laertes "Will you be ruled by me?" and Laertes responds that he will. From then on, the game is on for Claudius. All he has to do is convince Laertes to kill Hamlet and all of Claudius's problems will be solved and none of the responsibility will fall on him. He convinces Laertes to challenge Hamlet to a fencing match and convinces him with a long story that Hamlet is jealous of Laertes's skill. By appealing to his ego, he overcomes any qualms Laertesmay have had about possibly losing to Hamlet. Then, to ensure the revenge, they both agree to poison not only the sword by a cup of wine. If all goes to plan, Claudius will look completely innocent of the death. The final piece of his management of Laertes is his assertion that they must act definitively because he understands that the things one want to do need to be done quickly. He says, we should do it because
We should do when we would; for this "would" changes,
and hath abatement's and delays as many
As there are tongues, are hand, are accidents.
Claudius is echoing some of the same ideas that Hamlet talks about in the "To be or not to be" soliloquy in regards to how thinking and the passage of time delay the momentum of action. Claudius doesn't want there to be any delay in their plans against Hamlet. He is the master of manipulation in his actions with Laertes and he is using Laertes to achieve his ends.