Would a dahlia die if it were cut back now?

We tried this year starting a dahlia into growth in a pot which we kept in the porch. However, I think it must have been too warm for it in the porch and it's grown very, very tall and spindly. Could we cut it back now in the hope that it might grow more branches lower down or would that kill it?

 

I think you would get away with it, just dont cut too low, aim to cut just above a leaf joint.

 

Pete,
Thanks for that advice. I'll give it a shot.