(CNN)- Beto O’Rourke announced Thursday he is running for president, entering the 2020 race with a call for Americans to look past their differences in order to confront the challenges facing the country. “This is a defining moment of truth for this country and for every single one of us,” the 46-year-old Democratic former congressman from Texas said in a video announcing his candidacy. “The challenges that we face right now, the interconnected crises in our economy, our democracy and our climate have never been greater.” “They will either consume us, or they will afford us the greatest opportunity to unleash the genius of the United States of America,” he…