How does federalism enable people to particpate in their government?

In any democracy, the people have the ability to
participate in their government.  In a federal system, they simply have more
opportunities to do so.  This is because the government of their state (or province or
whatever the smaller units of government are called) is more accessible to
them.

The national government of a country is typically a
large entity that is based in a faraway city.  Ordinary people have little chance to
participate in it for that reason.  The state government, by contrast, tends to be much
smaller and much closer to home.  The people who represent you in a state government
represent a much smaller number of people than those who represent you in the national
government.  For this reason, you are much more likely to be able to have meaningful
interactions with your state legislator than with someone representing you in the
national legislature.

Federalism, then, gives people more
opportunities to interact with a government that is closer to them.  This means they are
more likely to have a chance to participate in their government in a federal
system.