Question

How might have Julius Caesar's death been different if he had lived in our century?

Answer 1

If a bunch Senators tried doing that to the President on the floor of the Senate on Capitol Hill today, they'd probably get nailed by the Secret Service.

More seriously, though, there are a number of safeguards in the Constitution that prevent abuses of power. Instead of relying on knives, Congress can vote to impeach a sitting President and eventually remove them from office using the laws of the land.