The &lt;a href="CDU/CSU"&gt;Christian Democratic Union/Christian Social Union&lt;/a&gt; (CDU/CSU), led by Chancellor Angela Merkel, won the highest percentage of the vote with 33%, though suffered a large swing against it of more than 8%. The Social Democratic Party (SPD) achieved its worst result since the Second World War with only 21% of the vote. Alternative for Germany (AfD)—which was previously unrepresented in the Bundestag—became the third party in the Bundestag with 12.6% of the vote, whilst the Free Democrats (FDP) won 10.7% of the vote and returned to the Bundestag after losing all their seats in the 2013 election. It was the first time since 1957 that a party to the right of the &lt;a href="CDU/CSU"&gt;CDU/CSU&lt;/a&gt; Union gained seats in the Bundestag.