Hi haver,
to return to your question:
I would cleary bid 1 Spade after 1 Diamond from pd.
But this is one of the great diesennses in bridge. Is it right to bid here or not. So Joes view has a lot of supporters and some merrits.
No need to repeat his valid arguments.
Otoh, you win in the following scenarios:
1. Pd has the very strong hand. This is not so unlikely as it may seems to be: RHO passes (maybe because of his own weak hand), which makes the two remaining hands stronger and stronger.
2. Your lho has a very strong hand: If you bid, you makes it much more difficult for them to compete.
3. The most likely scenario:
Both parties have about half of the deck:
So, your pd has about 14-15 HCPs. He won`t jump even with a fit, but he will raise your spades to 2 Spade and you have a big chance to play there, or he will bid 1 NT. And this is at least non-vul. another clear winner:
If the parties are on their way to make 6 or 7 tricks, it is always nice to bid NT from your side: If you make 6 tricks, you loose 90 against their NT but just 50 if you play and with 7 tricks you win just 50 against their 1 NT, but 90 if you make it. (besides the gifted tricks in defence, which are much more then the tricks you gain from the advantage of leading...)
4. Maybe your lho has a good hand with diamonds. He will pass and collect 100 or 150, while you are cold for 2 Spade.
(Besides, during one European Championship, a German team was defeated due to the following hand and bidding:
1 minor-pass-??
with xxxx,xxxxx,x,xxx. (Or maybe a jack somewhere)
The german table passed, for -150, the other table bid 1 heart was raised to four and made 11 easy tricks.
So, there is just one scenario, where I would expect to have a disadvantage: Pd has some 16+-18 HCP ands and jump to 3 Spade or 2NT. Then I maybe will get too high.
Kind Regards
Roland
P.S.: After 1 Club, 1 Spade is even safer to bid. YOu can always return to 2 or 3 Club later...)