<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:dem="http://www.democrat.org/"
  xmlns:rep="http://www.republican.org/">

<xsl:template match="vote">
   <xsl:copy>
      <dem:count><xsl:value-of select="rep:count - 432" /></dem:count>
      <xsl:copy-of select="*[not(self::dem:count)]" />
   </xsl:copy>
</xsl:template>

</xsl:stylesheet>