The issue is with this code:
#footer-widget-area .widget-title {
background: #4682B4 url('https://www.conservativepartyusa.org/home/wp-content/uploads/2012/01/title_bg.jpg') no-repeat;
-webkit-border-radius: 0px;
border-radius: 0px;
}
What’s happening is that you’re using an image to decorate the widgets header, but the image itself isn’t quite long enough to completely cover the header area and so a little bit of blue peeks out from behind the image. To fix it, you should find that code and change the first line to:
background: #fff url('https://www.conservativepartyusa.org/home/wp-content/uploads/2012/01/title_bg.jpg') no-repeat;
Unfortunately, I’m not 100% sure where that code came from, so you may wish to ask whomever set up your website for more information.