In the years between the end of the Revolutionary War and the outbreak of The War of 1812 the American merchant fleet grew dramatically. Although the majority of its trade continued to be with the British, the British public and government resented the added competition—in particular America’s trade with Britain’s perennial enemy, the French. During the Napoleonic Wars British ships often took to impressing American sailors to work aboard their ships—a provocative violation of American neutrality. In America the general response was outrage, and many prominent American politicians, like James Madison and Andrew Jackson, called for a “Second War of Independence” to finish the break with the Empire. Finally, many Americans living on the frontier were fighting a near constant conflict with displaced Native American populations and were offended to find that the British had been providing many Native American groups with weapons and supplies. The only false statement here is that it was the ascension of the Federalist Party that contributed to the outbreak of war. On the contrary, Federalist power was on the decline at the time. It was the Democratic-Republicans, and their significantly more staunch Anti-British feeling, that was in the ascension. 

The popular phrase "Remember the Maine, to Hell with Spain!" was influential in beginning the Spanish-American War later that year, even though Spanish involvement in the sinking of the Maine was not conclusively determined.

In the years immediately after the French revolution, diplomatic tensions between the United States and France were growing very quickly and seemed to be precipitating war. In an attempt to avoid war President Adams sent a delegation of diplomats to negotiate with the famous French diplomat Talleyrand. Talleyrand demanded a bribe to even meet with the American representatives; when word spread back to Adams, the United States’ politicians were outraged.  Many Federalists called for war and pressed Adams to release a copy of the report filed to him. Adams did release the report, but changed the names of the French diplomats to W, X, Y, and Z thus earning the whole business the title “The XYZ Affair.” In response to the public outrage over this seeming affront to American dignity Federalists were able to push through a massive upgrade to the United States’ Navy. However, Adams steadfastly refused to declare war and tensions ultimately died down. 

The Battle of Gettysburg finished an effort by Robert E. Lee and the Confederate Army to invade the North in Pennsylvania and create panic among the Union's populace.  The Union victory made Lee take his forces back into Southern territory, and from that point forward, the Southern Army was pushed further back on its heels.  The other significance of the Union victory was that it occurred on July 4, 1863, which was also the date that the Union won a victory at Vicksburg, MS, freeing up the Mississippi River.  The two victories brought an increasing focus on a smaller amount of Confederate Territory, and helped slowly bring the war to a close nearly two years later.

The Battle of Fort Sumter broke out in the early morning of April 12, 1860, with Confederate troops bombarding the tiny island fort in Charleston Harbor. Confederates claimed that it was their property, as it was in Confederate territory, while Lincoln refused to let go of Union Army installations. Forces led by Pierre Gustave Toutant Beauregard bombarded the fort for two days, until the Union troops surrendered, and the Confederates took control of the fort and the harbor. The Battle marked the official start of the Civil War, and many northern volunteers came forward. In slave states that had not joined the Confederacy, secession debates were enflamed once more, with Virginia, Tennesee, North Carolina, and Arkansas rounding out the Confederacy.

The Mexican-American War was initially incited by the United States' annexation of the Republic of Texas, which Mexico still claimed much of as its own territory. President James K. Polk had been elected by promising to spread American territory to the Pacific, and war with Mexico brought this about most easily. The United States won quite handily, quickly occupying New Mexico and California, and eventually occupying Mexico City. The Treaty of Guadalupe Hidalgo established peace by giving the present day American Southwest to the United States, and giving America a coast to coast territorial presence.

Edmond-Charles Genet was a French diplomat to the United States during the French Revolution. He was dispatched to the United States to try to encourage American support for the French wars against other European nations, primarily Britain. Citizen Genet ignored official diplomatic avenues, instead focusing on organizing popularly-supported mercenaries to fight Britain’s ally, Spain, in Florida. His success undermined Washington’s proclamation of neutrality, and Washington widely condemned his actions. The matter came to an end when a different form of government came to power, and Genet was branded a criminal in France.

The Intolerable Acts was the collective name for the series of restrictions placed on the New England colonies in the events preceding the American Revolution. The other answers were causes of the War of 1812.

The Battle of Gettysburg was the decisive turning point in the Civil War. Coming as the culmination of an invasion of the Northern states by the Confederate Army, the Battle of Gettysburg was an overwhelming Union victory. The Union win made the Confederate troops take a torturous retreat that weakened and morale. While the war would continue for almost two more years, the Confederacy was fighting off the back foot for the remainder of the conflict. Although Robert E. Lee resigned as commander of the Confederate Army after the battle, his resignation was refused, and he remained in the role until 1865.

The United States had always had a special interest in Spain's Caribbean colonial possessions, as they lay so close to the U.S. mainland. In 1898, the Naval battleship U.S.S. Maine was stationed in Havana harbor off the coast of Cuba when it sank under mysterious circumstances. The outcry in the press over the destruction of the American ship made the public and politicians clamor for a war to free Cuba from Spanish rule.