Netilat Yadayim: Blessing Before or After?

Question

These may not be the original sources for either shiTTah, but two early examples of either of them can be found in the Rambam, Mishneh Thorah - Hilkhoth Berakhoth 6:2 (mevorekh batteHiloh), and in the siddur of Rav Saadia Gaon, dinei berakhoth - ^amudh 88 (uv^aqav ghusl al-yadayin - wa-aHarei reHiSath ha-yadhoyim).

Essentially, the order for each method is:

1. Rambam: fill cup, say berakhah, pour water, and dry hands
2. Rasag: fill cup, pour water, say berakhah, and dry hands

My questions are:

• Which method is original?
• What is the source for each method?
• And mainly, with the general principle of making berakhoth before performing the miSwah (cf. b.PesaHim 7a-b), how can the second method be justified? And if it can be justified, does that make it original? (cf. first question)

Answer 1

In terms of your last question, two explanations are given by Tosafot (Pesachim 7b) as to why the blessing can/should be after washing:

וכן בנטילת ידים לא חילקו בין נטילה של אחר בית הכסא דלא מצי לברך קודם מיהו בנטילה יש טעם אחר לברך אחר נטילה קודם ניגוב כדאמרינן (סוטה ד:) האוכל לחם בלא ניגוב ידים כאילו אוכל לחם טמא
[By] Neilat Yadayim they did not differentiate between the washing after leaving the restroom when one cannot bless before [and] an addition reason [in this case] to bless after washing before drying is as it says (Sotah 4b) "One who eats bread without drying his hands is as if he ate impure bread" [so drying is still considered part of the Mitzva].

Both opinions are cited in Shulchan Arukh (OC 158) and modern practices are varied.