in politics當然是修飾scholar的，可是改動冠詞沒有必要。

定冠詞the可以加在名詞前麵指某個類別， 比如the scholar in politics vs. the scholar in religion. 我下麵引用Wiki上的解釋來說明一下：

“The definite article can also be used in English to indicate a specific class among other classes:

The cabbage white butterfly lays its eggs on members of the Brassica genus.”
另外，我查到一點東西似乎可以支持我的理解，即，the scholar in politics指政客，不論學識如何。請看下麵的鏈接：
http://books.google.com/books?id=mKg7AAAAYAAJ&pg=PA1&lpg=PA1&dq=%22the+scholar+in+politics%22&source=bl&ots=mSyzhu472k&sig=TwdDEnMhZ0_FaEpMjv4kE1-LEwc&hl=en&sa=X&ei=urrrUeu0FMWp4APly4HQDQ&ved=0CG0Q6AEwDw