stylistic:tone
Federal party level, election as chairman of the CDU

Kohl moved up into the federal board (Vorstand) of the CDU in 1964. Two years later, shortly before his election as chairman of the party in Rhineland-Palatinate, he failed at an attempt to be voted into the executive committee (Präsidium) of the party. After the CDU lost its involvement in the federal government for the first time since the end of World War II in the 1969 election, Kohl was elected into the committee. While former chancellor Kurt Georg Kiesinger remained chairman of the CDU until 1971, it was now parliamentary chairman Rainer Barzel who led the opposition against the newly formed social-liberal coalition of Willy Brandt.

As a member of the board and the executive committee, Kohl pushed towards a party reform, supporting liberal stances in education and social policies, including employee participation. When a proposal by the board was put to vote at a party convention in early 1971 in Düsseldorf, Kohl was unable to prevail against protest coming from the conservative wing of the party around Alfred Dregger and the sister party CSU, costing him support at the liberal wing of the party. To make matters worse, in a mistake during the voting process, Kohl himself voted against the proposal, further angering his supporters, such as party treasurer Walther Leisler Kiep.

Nevertheless, when Kiesinger stepped down as party chairman in 1971, Kohl was a candidate for his succession. He was unsuccessful, losing the vote to Barzel 344 to 174. In April 1972, in the light of Brandt's Ostpolitik, the CDU aimed to depose Brandt and his government in a constructive vote of no confidence, replacing him with Barzel. The attempt failed, as two members of the opposition voted against Barzel. After Barzel also lost the general election later that year, the path was free for Kohl to take over. After Barzel announced on 10 May 1973 that he would not run for the post of party chairman again, Kohl succeeded him at a party convention in Bonn on 12 June 1973, amassing 520 of 600 votes, with him as the only candidate. Facing stiff opposition from the left wing of the party, Kohl initially expected only to serve as chairman for a couple of months, as his critics planned to replace him at another convention set for November in Hamburg. Kohl received the support of his party and remained in office, not least due to the lauded work of Kurt Biedenkopf, whom Kohl had brought in as Secretary General of the CDU. Kohl remained chairman until 1998.

When chancellor Brandt stepped down in May 1974 following the unravelling of the Guillaume Affair, Kohl urged his party to restrain from Schadenfreude and not to use the position of their political opponent for "cheap polemics". In June, Kohl campaigned during the state elections in Lower Saxony for his party colleague Wilfried Hasselmann, leading the CDU to a strong result of 48.8% of the vote, even though it proved not enough to prevent a continuation of the social-liberal coalition in the state.