Defense Secretary and retired Marine General James "Mad Dog" Mattis is a great American warrior. His departure from the White House is a sad thing for those who have supported his amazing leadership over the decades, but the general and the president disagree on too many key issues for the relationship to continue.

Mattis understands that President Trump has a right to implement his agenda and in announcing his retirement, apparently over Trump's decision to withdraw from Syria, he stated as much.

“You have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position," he wrote in his resignation letter.

Before you jump to push the panic button over Mattis' retirement, keep in mind that Mattis' views are his views. There are other prominent generals who disagree with Mattis.

How many of you believe Trump should have remained in the Iran nuclear deal? Mattis did. Mattis also preferred a tougher line with North Korea and opposed a summit with Kim Jung Un. Mattis bristled when Trump demanded that NATO allies start paying for a greater share of their defense.

Mattis was a great field general but his view of key Administration policies was very different from Trump's, and I suspect yours as well.

Mattis is correct in acknowledging that Trump deserves a Defense Secretary who shares his view on important issues such as these. It is not only a "right," as Mattis proclaims, it is necessary if we are to have an effective foreign policy.

Barry Richard is the host of The Barry Richard Show on 1420 WBSM New Bedford. He can be heard weekdays from noon to 3 p.m. Contact him at barry@wbsm.com and follow him on Twitter @BarryJRichard58. The opinions expressed in this commentary are solely those of the author.