How to kill Social Security in 2 easy steps

How to kill Social Security in 2 easy steps
Here’s Kevin Drum advocating for step 1:

 the best way to address retirement security is to continue reforming 401(k) plans and to expand Social Security—but only for low-income workers. Middle-class workers are generally doing reasonably well, and certainly as well as they did in the past. We don’t need a massive and expensive expansion of Social Security for everyone, but we do need to make Social Security more generous for the bottom quarter or so of the population that’s doing poorly in both relative and absolute terms. This is something that every liberal ought to support, and hopefully this is the bandwagon that President Obama in now on.

Step 2:
Now that 3/4 of the population will be paying into a system to transfer their income to the bottom 1/4, you have instantly created a majority constituency that will benefit from killing the now-welfare program.
Why does Kevin Drum want to kill Social Security?