Michigan House members returned to work this week to decide whether they’ll give the state’s motorists a break on their highest-in-the-nation auto insurance premiums. In doing so, they’ll decide whether to dilute the nation’s most stringent no-fault auto insurance law, which requires drivers purchase coverage that provides unlimited lifetime medical benefits, and continue a trend among states of altering or even scrapping their no-fault laws. For many Michigan motorists — who pay on average $2,738 a year, more than double the national average — the decision would appear simple enough.