Removing them for anti-Constitutional rulings should be paramount, but relying on Congress to do so is pointless. You might get 2/3rds to remove a pro-Constitutional judge with a coalition of Democrats and weasel RINOs, but you’ll never get the reverse to remove the opposite.
Perhaps the idea of going to an election for Justices is a sound one. If they refuse to be accountable to the Constitution, they should at least be accountable to the electorate.
I think that having Supreme Court Justices nominated by the president and confirmed by the Senate is the least bad way to go about it. Elected judges will tend to rule based on opinion polls or on the opinion of campaign contributors, which is not the job of a judge and will bite us in the rear more often than not.
The only modification to the process that I would support is one that was floated a couple of years ago: have Supreme Court appointments be for 18-year periods instead of for life, with the justice slots being staggered so that a justice is named every 2 years. That would give each president two appointments per term, and would eliminate the possibility of a bunch of liberals retiring when the Democrats control the process so that they are replaced with liberals who will sit there for 35 years (if a bunch of liberals resigned, the Democrat president could only nominate replacements for the years remaining in each respective term). It would also reduce the problem of justices serving into senility. (While presidents would be able to nominate a justice to a second 18-year term, they would be unlikely to nominate someone so old that he would be feeble at the end of such additional term.)
But the best thing about having justices serve 18-year terms is that presidents would begin nominating justices who are in their 60s instead of in their 50s (since the 18-year term would eliminate most of the benefits of naming younger justices), which would make it less likely that a nominee’s views would be unknown. Why name a 50-year-old Roberts after only a couple of years as a Circuit judge when there’s a 62-year-old Circuit judge with a proven record who can also serve 18 years? No more stealth nominees.
Of course, such a change would require a constitutional amendment, but I think it’s an idea that can attract support from conservatives and liberals alike; liberals don’t want a Clarence Thomas serving for 40 years any more than we want an Elena Kagan serving for 40 years. Implementation would also be tricky, unless the amendment specified that the justice with the most years of service currently on the Supreme Court would see his term end on a certain date well in the future so as not to affect current justices too much (say, February 1, 2018) and the other current justices seeing their terms end two, four, six, etc. thereafter based on their years of service (with the person who replaces a justice whose term would end in, say, 2024 having his own term end that year even if he’s only been on the Court for a couple of years). I think it could all be worked out.
As for Congress impeaching and removing justices, I agree with DJ that it’s not something on which we can count.