Let’s take a look at an unassuming simple sentence that illustrates something we have to be careful about in our writing. Keep your eye on word groups: He funded opposition politicians to the government. We certainly understand the sentence; we know what the writer means, and so it passes the bar of logic. But we have to work a little to get to that meaning, and therein lies the problem. What the writer wants to say is straightforward enough, but the grammatical structure and resulting rhetoric are not.
Strong expository writing, the writing of fact and explanation we undertake most of the time, coheres; its elements cling together, accord, have something to do with one another by virtue of their proximity. In this way, a sentence unfolds its parts in an orderly manner, and as it unrolls, the reader is carried along inevitably to its meaning. An important point of sentence analysis is to discover whether a sentence conforms to this requirement of grammatical coherence, so let’s begins our test on the sentence in question here by isolating subject from predicate: He | funded opposition politicians to the government. In doing so, we make clear to ourselves visually (the subject has only one word) that whatever trouble we discover will lie in the predicate, that section of the sentence which contains the verb and all other words needed to complete the meaning of the statement. The predicate here contains a transitive verb (funded), which in turn requires the direct object opposition politicians. So far, so good.
Next, though, we come to the prepositional phrase to the government. This grammatical element is connected in meaning to the word opposition, and between the two stands the noun politicians, breaking the easy association of opposition to the government. Right here is the detectable cause of the extra work we as readers have to put into the sentence: we have to rewire the syntax as we read, reconfiguring the words to remove the obstacle of politicians (ever an obstacle, it seems) and let the meaning flow again. The writer has chosen to qualify the meaning of opposition, to say more specifically that their opposition was to the government, but simply rearranging the words only creates another problem: He funded politicians opposition to the government. That obviously won’t do.
So what to do? The word opposition is an abstract noun (most nouns ending in the suffix –tion are abstract), and it is here being employed as an adjective to the noun politicians, an acceptable thing to do if the writer were simply referring to the compound noun opposition politicians. An adjective that stands before its noun like this is called an attributive adjective, and it is meant to identify a permanent and defining quality of the noun it modifies; it names a quality that has congealed as part of the noun, so to speak, a quality that cannot, in the context, be taken away: an opposition politician is an opposition politician forever in the context of the sentence. But the writer here wants to say something about that quality of opposition itself, namely, that it was directed at the government; and if he wishes to say something, he needs to create another predicate, which can be done by finding the verb related to the abstract noun (the verb oppose), and putting its participle after the noun it modifies: He funded politicians opposed to the government. When an adjective follows the noun it modifies, it is called a predicative adjective; it creates a new predicate in disguise: politicians [who were] opposed to the government.
What results is a clearer sentence because its ideas are in order. The meaning unfurls, and we readers are in a better position to estimate the writer’s assertion. The art of clear writing precludes the idea that it is enough if the reader gets the gist of what we’re trying to say, or if we have to work only so hard and let the reader figure out the rest. It is always in our own interest to be clear, and keeping the grammar well organized is one way to assure we achieve that requirement.