Against tyranny, not for!
One way the government guards tyranny is called Federaism. Federalism prevents tyranny by preventing the state and national governments from getting all the power and protecting the nation and all the nation's people. The government also has twice the security by looking and checking off each others powers and making sure it's fair and tyranny won't start.
Another way the government prevents tyranny is cal seperation of powers. Seperation of powers prevents one person or branch to do whatever they want. If one branch gains all the powers, that branch can make the silliest most horrible laws. They can also pass horrible laws as well.
The next way the government prevents tyranny is something called checks and balances. Checks and balances prevents tyranny by allowing one branch to check each other and make sure that one branch has too much power. For example, the president can veto congressional legislation but congress can approve presidential nominations, overide a presidents veto and impeach the president from office.
BIG STATES VS SMALL STATES
The last way the government prevents tyranny is called bug states vs small states. This prevents tyranny because The Great Comprimise keeps the big states from over-powering the small states. If the big states have more power, then they could bully the smaller states. If the small states had equal representation, then they would be happier and it would be fair.