I also think this flexibility and his lack of government experience (along with that of his appointees) is sure to lead to fiascoes and scandals, as well as significant changes and accomplishments. (See Cowen's post on the latter.)
With that assumption, I don't agree with those who believe Democrats should be unfailingly confrontational, following the pattern of Republicans with Obama but going one better. I'd suggest a two-pronged stance:
- take every opportunity to point out Trump's lack of principles and flip flops--he'll provide sufficient ammunition.
- do deals when possible. Given past partisanship such deals are likely to split Republicans.
My underlying assumption is that the deals Dems reach with Trump will be successful, at least as contrasted to the issues on which we attack.