There are many scriptures that describe fasting, and most often, the Old Testament shows it was used as a way to seek guidance and blessing from Yahweh. In some cases it was a sign of repentance for sins committed:

1 Samuel 7:6,  “And they gathered together to Mizpeh, and drew water, and poured it out before the LORD, and fasted on that day, and said there, We have sinned against the LORD. And Samuel judged the children of Israel in Mizpeh.”

In some cases fasting was to ask Yahweh to do (or not do) something:

2 Samuel 12:22,  “And he said, While the child was yet alive, I fasted and wept: for I said, Who can tell whether GOD will be gracious to me, that the child may live?”

Ezra 8:23, “So we fasted and besought our God for this: and he was intreated of us.”

Sometimes fasting was done by an individual, and other times a group of people fasted that Yahweh might deliver them:

2 Samuel 12:16, “David therefore besought God for the child; and David fasted, and went in, and lay all night upon the earth.”

Jonah 3:5, “So the people of Nineveh believed God, and proclaimed a fast, and put on sackcloth, from the greatest of them even to the least of them.”

Let us not forget the New Testament scriptures regarding fasting:

Matthew 6:16-18, “Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward. But thou, when thou fastest, anoint thine head, and wash thy face; That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly.”

Acts 14:23, “And when they had ordained them elders in every church, and had prayed with fasting, they commended them to the Lord, on whom they believed.”

When an ecclesia is entering the time for elections and wishes the Lord's will be done, it certainly is in alignment with scripture for the brethren to fast to intreat Yahweh for His guidance and overruling; however, we do not believe the scriptures indicate that one may direct another to fast.  Kings of old may have ordered others to fast, but in the church, 'declaring a fast for all members' may interfere with the liberty we as brethren have in Christ.  There is a difference between offering a suggestion that the brethren might fast during the election season, and 'declaring' a fast for the ecclesia. In Christ, we each have a personal relationship with Yahweh. Fasting should be something that each child of God offers of their own free will, in secret.