Conviction comes with the tagline that it is based on an "incredible true story." Not all great stories make for great movies though.
The true story, which is pretty incredible, belongs to Betty Anne Waters and her brother Kenny. When Kenny was convicted of murder, Betty resolved to put herself through law school in order to take up his case and, ultimately, appeal his conviction. This process takes years, because Betty had to first earn her GED and then make it through undergraduate education, which she did while working primarily as a waitress.
The pitch sounds like a "can't miss" movie, and Minnie Driver, Juliette Lewis, and Melissa Leo combine with Swank and Rockwell to give the film a cast that is truly impressive. That the film is not more engaging can be attributed to two script and direction problems.
First, television dramas aside, the legal process is not inherently dramatic. A trial has moments of drama, yes, but Conviction is not really a courtroom drama. The bulk of Betty Anne's legal work that is shown in the film involves talking to people on the phone and visiting her brother in prison. That the most dramatic moment in the film comes off camera and that we learn about it after the fact rather than see it may be a testament to the film's verisimilitude, but it may also leave audiences wanting a drama rather than a civics lesson feeling a bit cheated.
The bigger problem with filming this narrative, though, is structural. Contemporary narrative film as a temporal, visual medium is good at showing action, immediacy, and consequence. It is generally less successful at capturing faithfulness, constancy, or persistence—qualities that demonstrate themselves, and grow in scope and meaning, over long passages of time. Conviction avoids the most stale and clichéd way of compressing time, that of the montage set to stirring music, but its plot arc is very repetitive. Betty's husband tells her to give up, but she keeps going. Betty has problems going to law school and working to support herself at the same time (her nasty law professor won't let her hand in a paper that is five minutes late), but buckles down and keeps going. Betty's kids feel neglected and ask to go live with their dad; Betty bites her lip, sends them off, collapses in tears, picks herself up, and keeps going. Betty's best friend questions whether or not she has done everything she can, so Betty fights with her—and keeps going.
These actions, these sacrifices, would certainly carry more weight if there were any dramatic tension attached to them, but in part because the film is based on a true story, most thoughtful viewers, even if they haven't seen the film's trailer that gives away 95 percent of the plot, will know already that Betty is not going to quit. I am certainly glad that she did not, and the fact that she did not makes her an admirable woman about whom a very interesting film could probably be made. Conviction is geared too much toward reviewing what happened to her and Kenny and not enough toward giving us insight into how they were able to accomplish and endure what they did. We are shown flashbacks of Betty and Kenny as children which hint that Betty may be fueled by survivor's guilt and gratitude for Kenny's protectiveness of her as a child, but these are handled pretty perfunctorily.