I agree. Even with an act of congress, it would never be guaranteed with certainty. Even with an amendment to the constitution, another amendment could come alo

I agree. Even with an act of congress, it would never be guaranteed with certainty. Even with an amendment to the constitution, another amendment could come along to nullify it (like how the 21st amendment repealed the 18th amendment). The author does have a valid point, however, in that knowing the income won't last forever will change how the beneficiaries behave.