Final answer:
The two pervasive judicial doctrines that often limit the taxpayer's ability to employ effective planning techniques are business purpose and substance over form.
Step-by-step explanation:
There are two pervasive judicial doctrines that often limit the taxpayer's ability to employ effective planning techniques: business purpose and substance over form. The business purpose doctrine states that a transaction must have a legitimate business purpose, and cannot be solely done for tax avoidance. The substance over form doctrine looks at the economic reality of a transaction rather than its legal form. Both of these doctrines aim to prevent taxpayers from using planning techniques solely for the purpose of reducing their tax liability.