Aaron David Miller and Richard Sokolsky assess Pompeo’s tenure as Secretary of State, and they find  him to be severely wanting:
We have worked for a half dozen secretaries of state in both Republican and Democratic administrations and rarely if ever have we encountered one more ill-suited for the job. Pompeo, who seems to be motivated by his own political ambitions and his desire to keep his job, has produced little of real consequence to advance the nation’s interest. If he continues on his current trajectory, Pompeo may end up being remembered as the worst secretary of state in modern times.
When Pompeo replaced Tillerson, there was a widely shared, mistaken belief that he could not possibly be worse than Tillerson, but in almost every respect he has proven himself to be just as bad at managing the department and much worse in advancing U.S. interests abroad. Tillerson was not a skillful diplomat, but at least he made an effort to be one. Pompeo sees his job mainly as acting as the president’s wrecking ball on the world stage. The previous Secretary of State famously avoided the press, but that is preferable to one who constantly berates reporters and lies to their faces on daily basis.
Tillerson was hamstrung by a poor relationship with the president and was poorly-suited for the job, but Pompeo has shown how much worse things can be when the Secretary of State is an unscrupulous yes-man willing to lie about anything and everything in order to keep the president happy. Pompeo has no more meaningful foreign policy experience than Tillerson had, but he is far more arrogant, partisan, and ideological in his approach to foreign policy issues. He isn’t as obsessed with “redesigning” the State Department as Tillerson was, but he arguably has less respect for the career professionals that work there. While he preens about defending State Department officials in order to stonewall the impeachment inquiry, he has presided over abusive subordinates and plummeting morale  as the diplomats in the department realize that he has no loyalty to them. Nicholas Burns commented  on this last week:
Secretary of State Mike Pompeo owes it to the men and women of the department to stand up for their nonpartisan service and defend them from the president’s bullying and persecution. Unfortunately, Mr. Pompeo seems unlikely to do this. His heated criticism on Tuesday of three congressional committees that are looking to depose diplomats involved in our Ukraine policy is not the sort of “support” our diplomats need right now.
Pompeo’s tenure over the last year and a half has been a miserable time for the department. It is fitting that the man who boasted about bringing back the department’s “swagger” is the one who has driven it into a ditch.
Miller and Sokolsky also rightly fault Pompeo for his disgraceful defense of the Saudis:
He has denied the CIA’s own assessment that Saudi Crown Prince Mohammad Bin Salman reportedly ordered the killing of Washington Post columnist Jamal Khashoggi and claimed instead that “there’s no direct evidence linking him to the murder.” His kowtowing to Salman has enabled the crown prince to pursue reckless policies elsewhere in the region. Exhibit A: Saudi Arabia’s ruinous military campaign in Yemen has inflicted untold misery as a result of its ongoing conflict with the Iranian-backed Houthis. Pompeo has been the point man in defending US military assistance to Saudi Arabia in its Yemen fiasco. His refusal to acknowledge the Saudi role in Yemen’s humanitarian disaster and willingness to place the blame solely on Iran strains the bounds of credulity to the breaking point.
Pompeo’s Yemen and Khashoggi lies are just some of the most glaring examples of how he seeks to deceive the public and Congress on issue after issue. His efforts to whitewash Saudi crimes and shift blame for the world’s worst humanitarian crisis away from the U.S.-backed Saudi coalition are some of the clearest proof of why he is the worst modern Secretary of State. One small consolation is that Pompeo’s destructive role as Secretary of State will stay with him and taint him for the rest of his career.