Is this intentionally ironic? Well, let me assume that it is not:

"Liberal social engineering" appears to me most likely to be referring to the liberal stance on social issues, revolve around altering our traditional norms. Understanding this, let me point out that removing slavery and removing segregation are both prime examples of liberal social engineering. In fact, they are certainly far more extreme examples of liberal social engineering than anything being proposed by anyone today.

The men of the past are not the men of today, and if some democrats had bad stances on issues in the past, that should not reflect our opinion of them today. Looking at your criticisms of present-day democrats, I do agree with your reverse discrimination criticism. But it appears to me that you criticize democrats today for engaging in liberal social engineering. Yet liberal social engineering is as likely to be an extremely good thing as it is to be a bad one. Just reading that paragraph, I thought it worthwhile to point this out.

As for the topic itself, I am not certain that I would say the party systems are filled with corruption. Certainly money drives politicians, and it some cases, it may be self-interest. But I would argue that most of the time, the individuals who are elected are indeed people who generally have the best interest of the nation in mind, and that isn't a sign of corruption.

Though perhaps it is a sign of corruption that when an issue finds its way into the eye of the public, politicians will often take whichever side of it is more popular at the time, regardless of whether that side is right or wrong. I would also agree that it is almost always those with the most wealth who are elected, instead of those with the right values, and I agree that our politicians are not necessarily the people most able to make the right decisions for our nation.