There are a number of factors that have grown over time to erode the United States as being a democracy. This problem stems from the rich and powerful always finding ways and means to gain advantage for themselves at your expense. This has led to the destruction of Democracy in the USA.  Let me list some top methods being used:

Money Buys Politicians

Keep this in mind, as a bench mark or ruler, for your decisions in deciding how successful our government is now. The US constitution was drawn up as a reaction to the tyranny of British rule, and especially the tyranny of the single monarch. Implied from this is the US should fight against authoritarian rule. The US “Supreme” Court in a series of decisions has overturned the original intent of the Constitution. It has “conferred on wealthy people the right to give vast sums of money. This ability of the rich to use their wealth to gain power over our political process and institutions is a new path toward tyranny. The Republican Party is supporting this effort to destroy our democracy.

The “Supreme” Court has germinated a new form of tyranny. The following “Supreme” Court judges are responsible for the nation being taken over by the plutocracy class:

• John Grover Roberts Jr
• Antonin Gregory Scalia, (died 2016)
• Anthony McLeod Kennedy
• Samuel Alito Alito

Note: All of the above judges were appointed by a Republican president.

• Neil M. Gorsuch was appointed by a Republican president and confirmed by a flawed Republican Congress that failed to follow past appointment rules.

Recommended Solutions:

• Promote, by every means, that the above “Supreme” Court justices be asked to resign, to step down, because they have made decisions that undermine our democracy.
• Oppose all future “Supreme” Court appointments dictated by the Republican Party.
• Campaign to remove or overturn all “Supreme” Court decisions where money is allowed to influence elections.
• Not allow any money to be paid to politicians or government employees, beyond their salaries.
• All government employees and elected officials can not work for any business related to government issues and oversight legislation for any business or organization after they retire from government service for five years.

Reference:
US is no longer a full democracy, EIU warns (https://www.cnbc.com/2017/01/25/us-is-no-longer-a-full-democracy-eiu-warns.html)

https://en.wikipedia.org/wiki/Politics_of_the_United_States and scroll down to this topic: Concerns about oligarchy and a diminishing democracy

The Supreme Court’s McCutcheon et al. v. FEC and Citizens United v. FEC decisions, “has this court conferred on wealthy people the right to give vast sums of money to politicians while undercutting the rights of millions of citizens to cast a ballot.”

Justice Stevens opposed Citizens United v. FEC. “A democracy cannot function effectively when its constituent members believe laws are being bought and sold.”[37] (https://en.wikipedia.org/wiki/Citizens_United_v._FEC)