WASHINGTON (AP) — Elizabeth Warren is releasing a new proposal to overhaul ethics rules at the Pentagon that would impose a four-year timeout before top Department of Defense officials could join the contracting industry.

Warren’s new plan comes ahead of a Thursday campaign appearance in Virginia. The Democratic presidential candidate cited Patrick Shanahan, the onetime Boeing executive tapped by President Donald Trump to be the next Pentagon chief, as an example of the “obvious potential conflicts of interest” her proposal is designed to prevent.