After you complete your research, you may have to include in your paper whether the death penalty should even be retained in the United States. There are those that believe it should be abolished and in fact, many western countries no longer have the death penalty. In the past few years, many death row inmates have been released due to new DNA evidence that exonerates them. Imagine how many may have been killed before any new DNA evidence could have freed them. And, as you have stated, a great many of the inamtes in prison today are minorities.
For an interesting viewpoint regarding this, I refer you to the work of Prison Fellowship and its founder, Chuck Colson, who was put in prison over his role in the Watergate scandal under President Nixon. After being released from prison, Colson started his ministry, Prison Fellowship, because he knows what it is like to be incarcerated and has a heart for prisoners - even the most vile offenders that throw feces at him when he visits the prisons. Colson's view is different from many others, and I encourage you to read about it.
Good luck on your research!
Since your thesis is arguing that the Death Penalty is discriminatory towards minorities and the poor, start with a research website that has evidence to support that argument. Amnesty International is a worldwide human rights organization that has been consistently against the death penalty in the US. The American website for this group has information about executions past and pending, as well as articles and arguments that will support your papers point of view (with cited sources). I've included the link below, as well as some other studies on minorities and the death penalty.
The first thing you need to do is research. You need to find data that supports your opinion. You can do this by researching individuals who have been sentenced and received the death penalty. You will also need to research what their crimes were. You need to find percentages of people in prisons given the death penalty and what their ethnicities are. For example, it is a fact that there are more African Americans in prisons than whites. To make it easy to understand, if there are 10 African Americans sentenced to death and only 2 whites sentenced to death then this does not prove that it is unfair because the ratio of African Americans to whites is different. You need more evidence to back your claim.
Another question I would ask here is what kind of lawyers are some minorities able to afford. Are they given representation by the court or do they hire their own attorneys. So basically, how good are their lawyers and could this be why they are sentenced more harshly.
There is a wealth of information about the death penalty, whether it is effective as a deterrent, and whether it is fairly imposed and administered. There are many web sites that advocate the moral and/or religious points of view, both for and against, but my answer focuses on resources dealing with the legal, political and social aspects of the death penalty.
I suggest you start with a source that collects and analyzes data regarding the death penalty, how it is imposed and on whom. A good starting point would be the Death Penalty Information Center, a well-respected non-profit organization that has been studying the death penalty in the U.S. since the early 1990s. The Center's web site is at
Another web site that addresses the death penalty issue, its effectiveness and fairness is:
This web site has links to pdf files of various articles describing research on the death penalty, its effectiveness and fairness of its imposition and administration.
Two other online resources you should investigate are the ACLU Capital Punishment Project:
and the NAACP web site:
One last group of web sites worth viewing are the Innocence Project web sites. There are Innocence Projects in many states, e.g., Illinois, Texas, Florida, Georgia, etc. They are non-profit legal organizations that offer legal representation to persons who have been sentenced to death. Death penalty appeals require an exceptionally high degree of skill and expertise that court-appointed attorneys in many states often lack. The Innocence Project web sites are well worth reading to find out about the issues of the fairness of the imposition and administration of the death penalty. Just "google" innocence project, and you'll find many of these organizations.
Finally, you will also find a lively debate in the pages of the New York Times and on web sites of organizations such as Amnesty International. Amnesty International opposes the death penalty, but you can find other sources of information in the articles on the site. The New York Times has vast archives that will provide you with a great deal of factual information and debate on all sides of the issue.
The sources I have described above should be enough to get you started on your research. During the course of your research, you will no doubt find additional sources of data and debate.