There's been a discussion of sustaining over at the By Common Consent blog, and its ramifications on church government. Though interesting to me, my most recent experience is more personal, and demonstrates the great opportunity that the act of sustaining someone to a calling has given me through the years, namely the chance to receive a confirming witness of the divinity of a particular call.
My wife was sustained to a new calling in our stake conference last Sunday. I had been there as the stake president issued the call. She and I had spoken in hushed tones over the two weeks between her receiving the call and being sustained. She told me of plans to meet with the women she'd serve with after they'd been sustained. I knew in all of this that she was well prepared and well suited to the calling she'd received, and I was glad for her to have this opportunity to serve and to bless others. I'd also had plenty of opportunities to feel the spirit as it related to her call. But I sensed this was her calling, and I didn't really need that spiritual witness.
Well it did come as her name was called in stake conference together with the other women with whom she'll serve, and as I raised my hand to sustain them. And that witness was sweet and gentle and clear. We weren't seated together at that moment (I was singing in the choir, and she was accompanying the choir on the piano), but she later reported she'd felt the same witness.
This isn't the first time that my act of sustaining -- which to me is a covenant to sustain -- has been supported by a spiritual witness. It has happened (sometimes) as I've sustained general authorities in general conference (even when the conference I'm participating in was half a world and and a week away from the original broadcast). It has happened as I've sustained my own counselors in a bishopric. It has happened as I've sustained my own local leaders as they've been called.
There may be many reasons for the sustaining vote in our meetings. One of them for me is the chance to feel again that spiritual witness that callings do come from the Lord.