How did the annexation of texas emerge as a political issue in the early 1840's? why were the democrats more in favor of territorial expansion than the whigs?

The Republic of Texas declared independence from the Republic of Mexico on March 2, 1836. At the time the vast majority of the Texian population favored the annexation of the Republic by the United States. The leadership of both major U.S. political parties, the Democrats and the Whigs, opposed the introduction of Texas, a vast slave-holding region, into the volatile political climate of the pro- and anti-slavery sectional controversies in Congress. Moreover, they wished to avoid a war with Mexico, whose government refused to acknowledge the sovereignty of its rebellious northern province. With Texas's economic fortunes declining by the early 1840s, the President of the Texas Republic, Sam Houston, arranged talks with Mexico to explore the possibility of securing official recognition of independence, with the United Kingdom mediating.

pepin the short[a] (german: pippin der kurze, french: pépin le bref, c. 714 – 24 september 768) was the king of the franks from 751 until his death. he was the first of the carolingians to become king.[b][2]

the younger son of the frankish prince charles martel and his wife rotrude, pepin's upbringing was distinguished by the ecclesiastical education he had received from the monks of st. denis. succeeding his father as the mayor of the palace in 741, pepin reigned over francia jointly with his elder brother carloman. pepin ruled in neustria, burgundy, and provence, while his brother carloman established himself in austrasia, alemannia and thuringia. the brothers were active in suppressing revolts led by the bavarians, aquitanians, saxons, and the alemanni in the early years of their reign. in 743, they ended the frankish interregnum by choosing childeric iii, who was to be the last merovingian monarch, as figurehead king of the franks.

it was the first major victory for the colonists.