Is Senator Paine right or wrong?

In the movie, Mr. Smith Goes to Washington, Senator Paine says:

“Thirty years ago I had your ideals. I was you. I had to make the same decision you were asked to make today. And I made it. I compromised – yes! So that all those years, I could sit in that Senate and serve the people in a thousand honest ways. You’ve got to face facts, Jeff. I’ve served our state well, haven’t I? We have the lowest unemployment and the highest federal grants. But, well, I’ve had to compromise. I’ve had to play ball. You can’t count on people voting. Half the time they don’t vote anyway. That’s how states and empires have been built since time began. Don’t you understand? Well Jeff, you can take my word for it.”

Is Senator Paine right or wrong? Is it impossible for a person with steadfast ethics like Mr. Smith to legislate? Is corruption inevitable, and if so, is it justified if it allows congressmen to serve the people in good ways, too? Is there an alternative to building states and empires that do not resort to the compromise of ethics? A strong case can be made both ways. Use examples if needed, and make a clear, coherent, and intelligent case.