"Deserted by his friends, he was forced to have recourse to those that had been his enemies." Here, if we write, "He, deserted by his friends, was forced &c.," he is unduly emphasized; and if we write, "He was forced to have recourse to his enemies, having been deserted by his friends," the effect is very flat.
Of course we might sometimes write "He was deserted and forced &c." But this cannot be done where the "desertion" is to be not stated but implied.
Often, when a participle qualifying the subject is introduced late in the sentence, it causes positive ambiguity: "With this small force the general determined to attack the foe, flushed with recent victory and rendered negligent by success."
An excessive use of the suspensive participle is French and objectionable: e.g. "Carelessly nature, and too much engaged with business to think of the morrow, spoiled by a long-established liberty and a fabulous prosperity, having for many generations forgotten the scourge of war, we allow ourselves to drift on without taking heed of the signs of the times." The remedy is to convert the participle into a verb depending on a conjunction: "Because we are by nature careless, &c.;" or to convert the participle into a verb co-ordinate with the principal verb, e.g. "We are by nature careless, &c, and therefore we allow ourselves, &c."
34. Suspensive Conjunctions, e.g. "either," "not only," "on the one hand," add clearness.—Take the following sentence:—"You must take this extremely perilous course, in which success is uncertain, and failure disgraceful, as well as ruinous, or else the liberty of your country is endangered." Here, the meaning is liable to be misunderstood, till the reader has gone half through the sentence. Write "Either you must," &c, and the reader is, from the first, prepared for an alternative. Other suspensive conjunctions or phrases are partly, for our part; in the first place; it is true; doubtless; of course; though; on the one hand.
35. Repeat the Subject when the omission would cause ambiguity or obscurity.—The omission is particularly likely to cause obscurity after a Relative standing as Subject:—
"He professes to be helping the nation, which in reality is suffering from his flattery, and (he? or it?) will not permit anyone else to give it advice."
The Relative should be repeated when it is the Subject of several Verbs. "All the pleasing illusions which made power gentle and obedience liberal, which harmonized the different shades of life, and which, by a bland assimilation, incorporated into politics the sentiments that beautify and soften private society, are to be dissolved by this new conquering empire of light and reason." ...