PHP Set default value in SELECT box

Hello,
I have a list of world countries in a select drop down box, other variables are added depending on the selection but I only want the United States to be selectable.
Given that the United States 'country_id' = 223, and 'name' = "United States", how would I set the default in the following code snippet:

<select name="address[<?php echo $address_row; ?>][country_id]" onchange="country(this, '<?php echo $address_row; ?>', '<?php echo $address['zone_id']; ?>');">
                   <option value=""><?php echo $text_select; ?></option>                                                         
                    <?php foreach ($countries as $country) { ?>                                                     
                    <?php if ($country['country_id'] == $address['country_id']) { ?>                  
                    
                    <option value="<?php echo $country['country_id']; ?>" selected="selected"><?php echo $country['name']; ?></option>
                    <?php } else { ?>
                    <option value="<?php echo $country['country_id']; ?>"><?php echo $country['name']; ?></option>                    
                    <?php } ?>
                    <?php } ?>
                  </select>

Select allOpen in new window

The 'addaddress()' function looks like this:

function addAddress() {	
&#9;html  = '<div id="tab-address-' + address_row + '" class="vtabs-content" style="display: none;">';
&#9;html += '  <input type="hidden" name="address[' + address_row + '][address_id]" value="" />';
&#9;html += '  <table class="form">'; 
&#9;html += '    <tr>';
    html += '&#9;   <td><span class="required">*</span> <?php echo $entry_firstname; ?></td>';
    html += '&#9;   <td><input type="text" name="address[' + address_row + '][firstname]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><span class="required">*</span> <?php echo $entry_lastname; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][lastname]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><?php echo $entry_company; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][company]" value="" /></td>';
    html += '    </tr>';&#9;
    html += '    <tr class="company-id-display">';
    html += '      <td><?php echo $entry_company_id; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][company_id]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr class="tax-id-display">';
    html += '      <td><?php echo $entry_tax_id; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][tax_id]" value="" /></td>';
    html += '    </tr>';&#9;&#9;&#9;
    html += '    <tr>';
    html += '      <td><span class="required">*</span> <?php echo $entry_address_1; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][address_1]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><?php echo $entry_address_2; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][address_2]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><span class="required">*</span> <?php echo $entry_city; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][city]" value="" /></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><span id="postcode-required' + address_row + '" class="required">*</span> <?php echo $entry_postcode; ?></td>';
    html += '      <td><input type="text" name="address[' + address_row + '][postcode]" value="" /></td>';
    html += '    </tr>';
&#9;html += '    <tr>';
    html += '      <td><span class="required">*</span> <?php echo $entry_country; ?></td>';
    html += '      <td><select name="address[' + address_row + '][country_id]" onchange="country(this, \'' + address_row + '\', \'0\');">';
    html += '         <option value="223"><?php echo $text_select; ?></option>';
    <?php foreach ($countries as $country) { ?>
    html += '         <option value="<?php echo $country['country_id']; ?>"><?php echo addslashes($country['name']); ?></option>';
    <?php }?>
    html += '      </select></td>';
    html += '    </tr>';
    html += '    <tr>';
    html += '      <td><span class="required">*</span> <?php echo $entry_zone; ?></td>';
    html += '      <td><select name="address[' + address_row + '][zone_id]"><option value="false"><?php echo $this->language->get('text_none'); ?></option></select></td>';
    html += '    </tr>';
&#9;html += '    <tr>';
    html += '      <td><?php echo $entry_default; ?></td>';
    html += '      <td><input type="radio" name="address[' + address_row + '][default]" value="1" /></td>';

Select allOpen in new window

Thanks in advance for any help.