No, they're not.

Should have been quite clear when Madoff ran a 20 billion USD ponzi for multiple decades and he got caught because his own sons turned him in at the FBI.

The SEC was not involved in Madoff at all (other than to make it worse my "auditing" Madoff multiple times and publishing that "all is fine nothing to see here").

The SEC is a government marketing agency to keep up the veil of US markets being fair and functional.