Grammar Politics is /are

I say that the following are correct. Do you concur?

Politics is everywhere in corporate America.

His politics is his personal business.

Politics is a heated subject.

But when do we use 'politics are'?

Thank you.

 

Disregard.

I found the following in The American Heritage Dictionary:

pol·i·tics (pl-tks) KEY

NOUN:

1. (used with a sing. verb)
   1. The art or science of government or governing, especially the governing of a political entity, such as a nation, and the administration and control of its internal and external affairs.
   2. Political science.
2. (used with a sing. or pl. verb)
   1. The activities or affairs engaged in by a government, politician, or political party:"All politics is local" (Thomas P. O'Neill, Jr.)."Politics have appealed to me since I was at Oxford because they are exciting morning, noon, and night" (Jeffrey Archer).
   2. The methods or tactics involved in managing a state or government: The politics of the former regime were rejected by the new government leadership. If the politics of the conservative government now borders on the repressive, what can be expected when the economy falters?
3. (used with a sing. or pl. verb) Political life:studied law with a view to going into politics; felt that politics was a worthwhile career.
4. (used with a sing. or pl. verb) Intrigue or maneuvering within a political unit or group in order to gain control or power: Partisan politics is often an obstruction to good government. Office politics are often debilitating and counterproductive.
5. (used with a sing. or pl. verb) Political attitudes and positions: His politics on that issue is his own business. Your politics are clearly more liberal than mine.
6. (used with a sing. or pl. verb) The often internally conflicting interrelationships among people in a society.

Usage Note:
Politics, although plural in form, takes a singular verb when used to refer to the art or science of governing or to political science: Politics has been a concern of philosophers since Plato. But in its other sensespolitics can take either a singular or plural verb. Many other nouns that end in -ics behave similarly, and the user is advised to consult specific entries for precise information.