The phrase to paper over the cracks means to use a temporary expedient, to create a mere semblance of order, agreement, etc.
The origin of this phrase is attributed to the Prussian statesman Otto von Bismarck (1815-98), who used a corresponding German expression in a letter dated 14th August 1865 during the negotiations of the Convention of Gastein, a treaty between Austria and Prussia which temporarily postponed the final struggle between them for hegemony over Germany:
Wir arbeiten eifrig an Erhaltung des Friedens und Verklebung der Risse im Bau.
We are working eagerly to preserve the peace and to cover the cracks in the building.
The earliest instance of to paper over the cracks that I have found is from The Essex Standard, West Suffolk Gazette, and Eastern Counties’ Advertiser (Colchester, Essex) of Saturday 16th March 1889, in an article on the question of whether Colchester should “at some time have a new Town Hall”—the fact that the phrase is in quotation marks indicates that it was already in use:
The people are beginning to get sorry now that the Jubilee scheme for a new Town Hall fell through, and are afraid that the building itself may soon fall through if something better than propping it up is not done. Although the expense to the rate-payers will of course be felt, I fancy the erection of a new building might be worthily accomplished by the aid of generous subscriptions, and I think this cannot be much longer postponed by the old Colchester cleric’s expedient of “papering over the cracks.”
Perhaps the phrase, as used in that issue of The Essex Standard, arose independently from any translation of the German expression used by Bismarck, because the practice of pasting paper over the cracks was common among people of humble means; for example, the following about a poor married couple that have just moved into a house is from The Pall Mall Gazette (London) of Saturday 18th May 1872:
The windows clatter like castanets to the gusts which come sweeping down the chimneys and howling up the stairs and along the passages. The gap has been stopped between floor and door; they have pasted brown paper over innumerable cracks and chinks.
The following picture, caption and passage from an article are from the Coventry Evening Telegraph (Coventry, Warwickshire) of Friday 28th March 1975:
One of the cracks in the walls of the nurses’ home.
£25,000 ‘to paper over the cracks’ in nurses’ home
To “paper over the cracks” in 14 rooms at the Walsgrave Hospital nurses’ home is to cost £25,000.
The Coventry Area Health Authority are to spend £25,000 in filling the cracks, said to be in partition walling, and covering the walls with a flexible form of plastic sheeting which will allow for any further fine cracking that occurs.