The president is replacing aides who have tended toward caution and consensus with figures far more likely to encourage his more rash instincts and act upon them, and he is frequently soliciting advice from loyalists outside the government. As he shakes up his administration, Trump is prioritizing personal chemistry above all else, as evidenced by his controversial selection of Navy Rear Adm. Ronny Jackson, the White House physician, to lead the Department of Veterans Affairs.