Yes, I believe that special interests have ruined democracy. Though most of the dirty work of lobbyists and the like are done behind closed doors in hushed whispers, the damage they have caused the country are embarrassingly evident. At one point in time, our country was ruled by the people, and our voice mattered in all issues. Currently, however, public officials sell their soul in order to receive the lobbyists' money, agreeing to their terms while deceptively making promises to the public which they know they can't keep. These special interests have indeed ruined democracy.
The US Constitution grants every American the inalienable right to voice his preferences for how decisions that affect his or her welfare are made, through his or her right to vote. That informed participation by every and every citizen is the bedrock of healthy democracy. When special interests bring large amounts of pressure on democratic systems, they subvert the intent of the Constitution, and thwart the will of “we the people.” The most pressing current problem in the US today is the insidious infiltration and influence of corporate money into our legislative branch of government, subverting the concept of “majority rule,” the actual will of “We the People....”
These days, the people with the most money can buy influence. Corporations, which are headless entities that only exist to make money, are able to spend billions and practically buy votes through advertising and smear campaigns. They manipulate public opinion instead of inviting free discourse. Because disclosure is not open and transparent, voters often fail to see the way that special interest money is swaying them and skewing facts.
Special interests are ruining the political process. Special interests are called special interests because they are interests that are different from (and usually contrary to) the interests of the common people. For example, most people are against the idea of giving big banks and oil companies more money and power. And yet, they keep getting it, because they are powerful special interests, with powerful lobbyists, who completely circumvent the will of the actual people.
"Special interests" is a code phrase for "ideas we don't like." If it is ideas we do like then it is "power to the people." Ideas are necessary to the governance of a free people, and those people have the right to petition the government to ensure their ideas are heard and accounted for.