Backslide

We've come this far, so we can't stop now. I don't want to backslide.

These people will make us backslide.

He felt better for a little while, before his condition started to backslide.

[…] Monna Brigida, who had backslided into false hair in Romola's absence, but now drew it off again and declared she would not mind being gray, if her dear child would stay with her.

Despite backsliding in various parts of the globe, there's a very clear trend towards the decentralisation of governments.

Rich countries are backsliding on their commitment to agree to new WTO measures to help people in poor countries gain access to affordable medicines.