What could Millard Fillmore have done differently to potentially avert the Civil War?

Millard Fillmore was a unionist but not an opponent of slavery. He did not join many of his Democratic colleagues in the anti-slavery “Free Soil” party, established in 1848, and while the Civil War was raging, he was vocal in his objection both to the emancipation of slaves in the Confederate states and to the forming of black brigades in the North. His support of the so-called “Compromise of 1850” reflects his mildly pro-slavery views. The compromise would have been the president’s best chance to stop the war, and while it is viewed by most historians as having postponed war with the South, it also undoubtedly served to emphasize sectional divides between the Northern and the Southern people. It outraged a great many Southerners who wanted the right to continue promoting and expanding the slave trade in the North and, likewise, many Northern abolitionists who hated the idea that Northern federal officers would be forced to aid in the recapture of fugitive slaves.
Fillmore might have taken a more pro-slavery angle to appease the South. He might have allowed Texas to keep its territory above the Missouri Compromise line, which ran between slave and free states. Doing so would have appeased the South by granting it a foothold in the North. He might have required California to vote on the issue of slavery rather than being admitted as a free state by default, as was permitted by the compromise for the New Mexico and Utah territories. He might even have allowed for the continuation of the slave trade in Washington, DC, which would have been as much a symbolic as an economic victory for the South, a recognition by the nation’s capital of their beloved institution.
Such actions, however, would have alienated not only the large numbers of Whigs whose anti-slavery feelings were soon to find expression in the formation of the Republican Party, but also Fillmore’s Free Soil colleagues. Beyond politics, it might also have stirred radical abolitionists such as John Brown to act earlier than they did, thus bringing on the Civil War far earlier than it began in reality. Fillmore might have pursued a more assertive abolitionist stance by banning slavery and not just slave-trading from the nation’s capital in a symbolic rejection of the institution and by insisting that the New Mexico and Utah territories comply with the Wilmot Proviso, which banned slavery in territories seized during the Mexican-American war.
Of still greater significance, he might have opposed the fugitive slave law, which all but forced Northerners to become complicit in slavery by threatening both officers and citizens with heavy financial penalties for aiding fugitive slaves in any way. Had this draconian law not been in force during the 1850s, scandals such as the capture of Anthony Burns in Boston, which provoked a surge in abolitionist feeling in the city and beyond, might have been avoided. Without the sharpened awareness across the North that stemmed from this law, it is also likely that the portrayal of fugitive slaves in works such as Uncle Tom’s Cabin would not have awoken such sympathies in Northern hearts.
However, it is unlikely that the South would have accepted such reforms, since they would have constituted an explicit stance by the government against slavery, a stance that would provoke the South to war ten years later with the election of Abraham Lincoln and would also seal slavery in the South, preventing its expansion and dooming it to inevitable decline. Overall, it is unlikely that Fillmore could have prevented the Civil War by any means, since the issue of slavery was too monumental for one man to diffuse.