The modal verbs that convey a sense of obligation and necessity are should , must , need , ought to , got to , and have to . Some examples of policy claims are We should legalize drugs. We ought to register and license guns the same way we do automobiles. Drivers under the age of 25 with even the slightest amount of alcohol in their blood should have their licenses revoked for 5 years. We need to tax alcohol and tobacco more heavily since the use of those products accounts for a disproportionately large fraction of medicare costs.
S upporting a policy claim can be very difficult.
The writer must first convince the reader that current policy on some issue is not working, second convince the readers that the writer has a better policy, and finally move the readers to act on the writer's suggestion.