Try looking at it this way.  From looking at your $header, you are looking for 3 columns?

    foreach ($obj_response as $response) {
    if ($str_current_country == $response->country) {
      $rows[] = array($str_current_country, $response->wider_dissemination, $response->response);
    }

**EDIT**

    // Test Output
    $header = array(t('Country'), t('Wider Dissemination'), t('Responses'));
    $rows = array();
    $rows[] = array('US', 'Extremely Wide', 'Response');
    print theme('table', array('header' => $header, 'rows' => $rows));

The test works for me.  Maybe something in your response value is messing with it?