One chief might allow the SWAT commander authority to make tactical decisions, while the next chief will only allow him/herself to make the call. This translates into if/when/how/why/where use of force (including less lethal, chemical, etc.) being "allowed." A growing trend today is not allowing SWAT to do anything "offensive," unless specifically OK'd by the Chief. In many cases, the result is a return to "green light, red light," and "sit, wait, and talk."
Is there any wonder why there is so much "disconnect" between the top and bottom in so many agencies/departments? Consider yourselves very fortunate if you work for a "good" chief/sheriff, one who understands and supports you, and earns the respect of his/her officers and the public, and even the media and politicians. It's called leadership—with a capital L.
However, to those of you less fortunate (you have a lot of company), while you have my sympathy/empathy, there is little time to feel sorry, because the reality of today's street dangers won't let you. Improvise, adapt, overcome. Do the job the best you can, act in good faith, and do it every time. Do the right thing, and do it all the time. It's called being a professional, which is exactly what you are.
Easier said than done, you say? And you'd be correct. But no one ever said ours is an "easy" profession. The exact opposite is the reality of policing in today's constantly changing society. Yes, we're (too) often caught in the middle of political power struggles, but we still have to do the job as professionals, and strive to do the right thing all the time—because it's the right thing to do.
If you're lucky, you'll outlast most of your chiefs/sheriffs, and someday you might even become the next chief. Stranger things have happened. The current chief of my department and I worked together as SWAT sergeants for 12 years. If you make it to the top, don't forget where you came from, or those who fight in the trenches, because they will be counting on YOU for their very survival.