Again and again, for almost eighteen years, he fought against censorship, with even greater energy when the freedom of the press won in 1832 after a short time had to yield to the decrees of the Bundestag of the German Confederation led by Austria.

That the second chamber held to its right, over strong objections from the government, to develop an integrated German Confederation of national unity and civil freedom, this was essentially Welcker's doing, since he never contented himself with just improving the legislation and administration of the grand duchy with his numerous proposals, but always kept his eye on the grand scheme and early on introduced in the chamber the principles for the reform of the Bundestag and brought them to debate.

In the short time that freedom of the press reigned in Baden, Welcker used it to establish a liberal newsletter, Der Freisinnige ("The Independent"), where he published a series of articles advocating emphatically for sincere and continuing constitutional reform and for freedom-enhancing lawmaking, while on the other hand energetically speaking against the tendency which was gradually taking root in southern Germany to seek by revolutionary means what the governments denied.

At the same time the University of Freiburg, where along with Karl von Rotteck and other like-minded colleagues, he had taken a hostile attitude toward the tendencies the government was led by, was closed indefinitely.

Welcker, in his constitutional proposals at these proceedings, opposed radicalism sharply as well as unification enthusiasms and spoke out for the right of the members of the existing governments to participate in the new formation of Germany.

On 14 March 1848, the Baden government had named Welcker as its Bundestag representative, having informed Baron von Blittersdorff that it could no longer retain him in that position against the public opinion of the land.

In this capacity, as well as for the Frankfurt Parliament (also called the National Assembly), as a member of which the 14th Baden precinct had elected him, he now had the duty of concerning himself with German constitutional questions.

In addition, Welcker was entrusted by the Reich's caretaker with many diplomatic missions, to Vienna and Olmütz among other places, where he was to discuss with the Austrian government certain conceding concessions to the revolutionaries, and to Sweden, where he brought along the young Victor von Scheffel as a secretary.

During the discussion of the leadership question in the National Assembly, Welcker parted company with the large Centrumspartei which he had previously belonged to, since, after his diplomatic journeys, he could not get friendly with the idea of having Prussia at the head of Germany.

He now made a major about-face, and, without informing his own party (Vereinigung des Pariser Hofes), on March 12 in the National Assembly he made the surprising proposal to "accept the entire imperial constitution as it now stands after the first reading before the constitution committee with regard to the wishes for a government, and accept it with a single vote," and have a deputation take it to the king of Prussia to show him his naming as the hereditary Kaiser.

But in the development of German liberalism in the fight against the reaction of the Bundestag led by Austria and Prussia, Welcker had taken a prominent role, so that in the history of political life in Germany his name next to that of Rotteck and other early fighters, especially those of the 1830s, is assured of a persistent recollection.