When President Trump declared a national emergency that even he admitted wasn’t necessary, he broke longstanding norms about how a president could wield power designated to Congress in order to address crises. Now that he has the declaration in hand, his administration has continued to run roughshod over the norms that make up the unofficial rules of the game in Washington.

The latest example of this is acting Defense Secretary Patrick Shanahan’s decision to simply move money around within the Pentagon’s budget without seeking approval from Congress.

On Monday, the Pentagon transferred one billion dollars from its personnel fund to a fund for counter-narcotics which will be spent to build barriers at the southern border. Normally, that sort of transfer would be done only after notifying and consulting with the relevant committees in the House and Senate.

But knowing that lawmakers who had already roundly rejected funding for Trump’s wall weren’t going to approve the transfer, Shanahan took the authority to shift funds granted to the Pentagon by Congress and ran with it.

In doing so, the Pentagon violated a long-standing gentleman's agreement that conditioned some budget flexibility for the Pentagon on consultation with lawmakers.

For the Trump administration, this quick and dirty fix is apparently worth it even if it means the Pentagon will lose that control over its budget it in the future.

On Tuesday, Shanahan defended the move to lawmakers. When warned by House Armed Services Chairman Adam Smith, D-Wash., that shifting funds to bankroll Trump’s wall would likely mean “the Appropriations Committee in particular would no longer give the Pentagon reprograming authority,” Shanahan tacitly agreed. As he acknowledged: “We understand the significant downside of losing what amounts to a privilege.”

The immediate cost of Trump’s wall will be tallied in lost dollars for needed construction projects, repairs put off for another year, and an inability to respond to new needs.

The long-term cost, however, will be measured in the destruction of the unwritten norms and agreements that underpin the functions of government. Although that distrust is tied to the Trump administration, the lingering fear of easy abuse he has made so clear will likely rewrite relationships long after he leaves office.