AL78, on 2019-December-16, 17:21, said:
I tend to raise partner immediately if I have support in a competitive auction, even on thin hands. On this hand it has some mild pre-emptive value in preventing West from bidding their major at the one level. If I were West, I would have bid 2S which East would raise to game. If my partner raises my one level opening over a double I am not playing them to have much defence.
A single raise of a minor over a double doesn't show much, but it ought to show something beyond four pieces. You have absolutely no offense at all. No useful high cards (C honors may or may not be useful); no particularly useful shape; your D support is lousy. A raise ought to be slightly better than this. If your 4 HCP were the Ad, so that you had Axxx of D and out, I could stand a D raise.
Beyond that, a 2D bid has absolutely no preemptive value at all. The bidding isn't going to die at 2D. If advancer passes and your partner has a minimum, then doubler is going to X again or else bid a suit.
All the 2D bid does is provide advancer a convenient way to distinguish bad hands (he will pass) and 6-9+ hands with a major (he will bid 2M). Here, advancer will bid 2S. Doubler can now bid 3D to force game, and then it will go 3S - 4S.
If you pass the X, advancer will bid 1S. Doubler now has a major, major headache. He is no longer good enough to cue bid, as advancer could be broke. It will actually be much more difficult for the opponents, oddly enough.