people respond to incentives
What the hell? You dare... You must be an evil market fundamentalist to believe... That is incredible.
Actually as a market fundamentlist myself, I know that, even when equivalent statements have been seen as insulting by quite a number of left wing people.

However, the basic income doesn't pay people for not working, but regardless of work. There is the same problem in Germany, and it has nothing to do with income taxes. The problem is the sharp reduction of benefits, when people earn their own living. The following picture is out of a book from a job market economist. On the Y-axis gross income is plotted, on the X-axis corresponding net income for a family of two adults and 2 children, assuming there is no capital or capital income in this family and all income is generated by work or payment of the gov't.
The red line shows the situation in 2003. As you see for the net income it didn't play a significant role, if this family earned nothing, or up to 1500 Euro, for the net income.
The Hartz reforms have improved this situation, but introduced a 'cave', where it can happen, that you have even less net income, when you increase your gross income from work. The blue line is irrelevant so far, as this is the line, the author proposes with an own model.

So even currently the effective marginal tax/benefit reduction rate is close to 80% for quite a way on this graph. The basic income would work as kind of combi wage, where you can determine the marginal tax rate as you want, but 30-50% will be still largely better than the 80% we have currently. After all it matters how much is left, and with 40% tax rate 3 times as much is left as with 80% tax rate. In the end the basic income would not give the most none-working people in Germany one cent more, but those with very little incomes. It reduces the disincentive of unemployment benefits.

Not even the Greens support it around here anymore.
I'm not 100% sure if it is part of the green basic program in Germany, but they are rather open to it. High ranking greens have already promoted the idea with using it as a corresponding measure to even more increased energy and environment taxes. There is as well some support from the conservatives and some more from the commies. Combi wages, as proposed by the conservatives and liberals, would be as well lead into this direction.
The only party, which totally opposes the idea of a basic income are the social democrats. There are plenty of arguments, which essentially culminate in either in the idea, that it is very difficult to explain hard working low earners, that people who don't try to get a job should be rewarded without strings attached, or that - as they believe it is the meaning of live to work - a basic income would diminish the value of their work.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers