Efforts to shield President Trump from a primary challenge have reached Michigan, where Republican leaders are rewriting party rules for winning GOP delegates to the 2020 nominating convention.

The move, overseen by the Trump campaign and the Republican National Committee, is part of a coordinated, national strategy to grease the president’s renomination. Republicans in state after state are amending party regulations governing the allocation of delegates in primaries and caucuses, effectively blocking GOP challengers from earning the right to have their name placed in nomination at the convention in Charlotte.