In each of the following sentences, one or more hyphens is missing from a phrasal adjective, but another solution is available: A relaxation of the syntax is recommended, as explained following each example and demonstrated in a subsequent revision.
1. We can expect to see lighter touch regulation in the banking sector.
The hyphenation problem here is a lack of a hyphen—“lighter touch,” as a phrasal adjective modifying regulation, should be hyphenated: “We can expect to see lighter-touch regulation in the banking sector.” Better yet, however, because of the somewhat obscure expression, it might be better to introduce the phrasal adjective as a modifying phrase following the noun: “We can expect to see regulation with a lighter touch in the banking sector.”
2. It is not unreasonable to question whether a Republican majority backed replacement plan is possible going forward.
The three words preceding the phrase “replacement plan” unite to provide more detail about the plan and should, therefore, be styled as a phrasal adjective, with hyphens connecting the words: “It is not unreasonable to question whether a Republican-majority-backed replacement plan is possible going forward.” However, this treatment is somewhat cumbersome, so a solution equivalent to the one in the previous example is merited: “It is not unreasonable to question whether a replacement plan backed by a Republican majority is possible going forward.”
3. The risks may not manifest themselves over an annual period or a three to five-year planning horizon.
The phrasal adjective preceding “planning horizon, with an implied instance of year after the first number as well (and similarly hyphenated if year explicitly appears), requires suspensive hyphenation: “The risks may not manifest themselves over an annual period or a three- to five-year planning horizon.” However, to mitigate the complexity of the sentence, consider placing the modifying phrase after the noun, with hyphen(s) omitted: “The risks may not manifest themselves over an annual period or a planning horizon of three to five years.”