[Avodah] Not saying Tachanun (was Yom Haatzmaut)

[Ben Waxman via Avodah]

On 4/29/2015 11:53 AM, Kenneth Miller wrote:
> #1 Perhaps, since the day when Tachanun first began, the list of days 
> has never changed. What did happen (perhaps) is that some places said it 
> on Purim Katan, and some places did not. Over time, the minhag of 
> skipping it spread to more and more places, but that's somewhat 
> different than if a community would suddenly decide that they had a new 
> appreciation for the significance of the day, and hence wanted to stop 
> saying Tachanun.

I don't think so. The Rambam, Hilchot Tefila 5:15 lists the days that
one doesn't say Tachanun (or nifilat ah'payim in his words) and the list
is much more restricted than our list (Shabbat, Chaggim, Rosh Chodesh,
Chanukka, Purim, and the Mincha before them). He writes that this is
the minhag b'kol yisrael. I am not a Rambam expert so I don't know what
to make of those three words (minhag, b'kol yisrael). If it is a minhag
does that mean that it can change? What is b'kol yisrael (I realize that
at the time of the Rambam, Ashkenaz was the middle of nowhere)? But it
would seem from the Rambam that at his time, the Jewish world didn't
skip those other days.

>  #2 A good example to my mind is the chasidic groups who celebrate 
> the anniversary of their rebbe's release from prison. Would RYBS insist 
> that they say Tachanun on such days?

I had the same question.

Ben