Generally, "logrolling" is used to criticize legislators for passing legislation that is, for example, bad for the country, but passed because so many legislators get pet projects included.
More rarely, "logrolling" can also reference any trading of favors. There is also a lumberjack sport that is generally spelled as two words: "log rolling".
The expression, logrolling, is thought to come from neighbors helping each other to roll logs. One person could cut a tree down, but help was needed to move the resulting log. Of course, the help was reciprocated.
Voters disparage legislative logrolling, but all legislators do it.
Sectionalism, logrolling and a series of near-fanatical movements—of which the "free silver" movement that embroiled Lamar was only the beginning—plagued Senate deliberations on domestic economic issues.
John F. Kennedy -- Profiles in Courage
He did not desire to be caught in any of the logrolling factions, though for Terry Wickett, still in France, and for Terry’s rough compulsion to honesty he was sometimes lonely.
Sinclair Lewis -- Arrowsmith
It is impossible to imagine the austere Puritan divines of Massachusetts inventing such verbs as /to cowhide/ and /to logroll/, or such adjectives as /no-account/ and /stumped/, or such adverbs as /no-how/ and [Pg045] /lickety-split/, or such substantives as /bull-frog/, /hog-wallow/ and /hoe-cake/; but under their eyes there arose a contumacious proletariat which was quite capable of the business, and very eager for it.