Since or Because?

Since Donald Trump has become president, there have been many protests across the USA.

In normal English, the term “since” can mean “because” or a period of time after an event. Both uses are fine. However, in the above sentence, the meaning of the author is not clear. Does the author mean the protests happened because Donald Trump became president, or does the author mean the protests happened after Donald Trump became president?  The two concepts are closely related (and perhaps the author means both), but in academic writing, a sentence like this should be avoided. It is important for the meaning of the language to be precise so that the ideas are clearly expressed.

To avoid ambiguity in academic writing, it is best to use “since” only to refer to time and use “because” elsewhere. Hence, the author would write

Because Donald Trump has become president, there have been many protests across the USA.

to convey the cause of the protests, and

Since Donald Trump has become president, there have been many protests across the USA.

to convey when the protests happened.