Remember Mr. Smith Goes to Washington? That uplifting story about how a regular Joe exposes the graft in Washington, bringing down a corrupt political machine? He probably prevented the creation of hundreds of jobs (in the Great Depression, no less) and stopped rural communities from getting access to electricity. He also alienated the President and lost his state most of its power and influence in the Senate, so when World War II rolls around in a few years, they're not going to get much of the economic boost that came from the increase in industry. (See here.)
Wasn't the dam a fraud? How was it supposed to create jobs?
That was what the Taylor machine was telling people. The whole second half of the film is about how people are being TOLD the dam will create jobs, etc. but it's all a scam. This is the whole reason Smith's filibuster doesn't work (until Payne snaps).
It wasn't a scam or a fraud, it was a graft. Taylor bought up land along Willet Creek and had his puppet senator propose a bill to build a dam on the creek. To construct the dam, land along the creek would have to be bought by the government, since it was a government sponsored dam, and Taylor would make a very nice profit.
The project itself was legitimate, and WOULD have created jobs, irrigation and given electricity to people who probably never had electricity in their lives. So by stopping the bill, Smith denied his constituants a hydroelectric dam that would have improved their lives, and alienated them from the Senate.
Unlikely. The dam location was probably close by Smith's home since he expresses great familiarity with it and they are clearly getting along fine, with electricity for that matter. While The Boys Camp being in the same place as the dam was what got his attention in the first place, Smith opposes the dam because from his own research earlier he knew the area did not need the dam at all. That's why he was totally baffled that they would build one there in the first place since, "There are other areas in the state that really need the water!" Building the dam there would have deprived an actual needy location of the money needed for a dam.
So, at the end, when Smith collapses, Pain tries to commit suicide by shooting himself, only to have the gun wrestled away from him. In response, he announces that everything Smith said was right, vindicating him. Now, what would've happened if he was successful in his suicide attempt?
There would be an investigation into his death and as a result a lot of facts would come out about the dam. Recall that in the beginning, Taylor told Paine that he wanted the bill to go through without any fuss so that people would not ask probing questions about it— those would be the exact same questions that would come up with a dramatic death hanging over the bill. Taylor's machine would probably try to spin it as Smith's crooked actions driving his honorable friend to suicide, but most likely Smith would be vindicated in the end, just after several months rather than immediately.
Taylor's master plan was to make Jeff Smith the legal owner of the land which he wishes to dam. How does Taylor profit from this?
Presumably he would have gotten some kind of large kickback for helping to build the dam.
He had the children who would benefit from the camp donate so he could buy the land outright. By Taylor giving Smith the land, it would make Smith look like a crook, since he wouldn't need to raise funds to buy it, and would thus be "pocketing the nickels of school children."
If Smith was really a crook who owned the land around Willett Creek, as Taylor's character assassination alleged, then he would have had no good reason to oppose the bill put forward by the corrupt senators in favor of his own bill— either way he would be the one to get the money!