Who/what is the adversary patrick henry speaks of?

British.

Explanation:

The speech was made to the Second Virginia Convention on March 23, 1775, by Patrick Henry. The speech that he gave later came to be famous as "Give me liberty or Give me Death."

The speech was delivered to the convention of Virginia, as they were debating over the matter that whether they should send Virginian troops in the Revolutionary war or not.

The Revolutionary war broke between the Great Britain and the thirteen colonies in the North America, by Americans to seek independence from the monarchy of the Britain.

Henry, delivered this speech and encouraged the convention that they should let the Virginian troops go to war raging against the British.

So, the adversary spoken of in the speech by Patrick is British.

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