At one time you were expected to be a subject of a king or queen in the UK, you're allegiance was expected. That disappeared from the 1940's onwards. The only ones that have to do that are the MP's to take their seats in the commons.
But the "subject" was raised about Americans being subjects, I assume to a flag -
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So as Americans still pledge allegiance, they're obviously subjects.
So the question is, are Americans subjects of the US flag, their government, or their president?
But the "subject" was raised about Americans being subjects, I assume to a flag -

What is the difference between a U.S. citizen and a U.S. subject? How does this affect their legal standing as far as rights go?
Answer (1 of 8): Well, not to mince words but the words do bind the subject of those words. So, let’s just take a brief gander at the fork in the road when the concept of a U.S. citizen took an interesting turn: The term “subject” in the first section of the 14th amendment is a verb as opposed t...
So as Americans still pledge allegiance, they're obviously subjects.
So the question is, are Americans subjects of the US flag, their government, or their president?