One is not allowed to dance during the mourning days of s'firas haomer (Mishna B'rura 493:3). According to all major customs, Yom Haatzmaus (Israel's independence day) falls during the mourning days (as it's the third, fourth, fifth, or sixth of Iyar; see e.g. MB 493:14–15). Yet some orthodox synagogues and schools have programs on Yom Haatzmaus in which people are encouraged to dance.
Now, a sandek is allowed to shave in honor of the b'ris mila (MB 493:12), but AFAICT dancing is still forbidden to him.
So my first question is:
- Are the mourning restrictions dropped completely by those who allow dancing on Yom Haatzmaus, much as they are on, e.g., lag baomer, or is it only dancing that's permitted (in honor of the day, much as shaving is permitted for a sandek in honor of the b'ris mila)?
Now, the custom is to observe mourning restrictions thirty-three days; which thirty-three days varies by custom. See e.g. MB 493:14–15. The examples he gives, though, count lag baomer as one of the thirty-three days even if mourning restrictions are not kept during its daylight hours, because mourning restrictions are kept during its evening (MB 493:10, but see :11). So if the answer to my first question is that all mourning restrictions are dropped on Yom Haatzmaus, my next questions are:
- Are all mourning restrictions dropped from Yom Haatzmaus both evening and day?
- Is Yom Haatzmaus, like lag baomer, counted as one of the thirty-three days with restrictions? Or do those who keep no restrictions on Yom Haatzmaus count thirty-three days of restrictions besides it?
(Of course, because of the considerations in the paragraph just above, these last two questions are of interest in light of one another.)
A sourced answer (e.g. citing a t'shuva addressing these issues) would be ideal, but an answer telling what people do generally is also of interest.