There is much joy in liberal circles these days about the plight of the GOP and conservatism. Democrats now control the presidency, the House, and the Senate. President Obama’s approval ratings are above 60 percent in most polls. The public is much more optimistic than it was at the end of last year. Meanwhile, the percentage of Americans identifying themselves as Republicans is at or near record lows.

These are undoubtedly heady days for Democrats and liberals, and they should enjoy them while they can. Moments like these can be fleeting in politics (less than five years ago, Republicans controlled all three branches of the federal government, a majority of governorships, and a plurality of state legislatures). It all depends on what unfolds. And on this point, it is worth keeping in mind the words of Lincoln.

In a letter, Lincoln engaged Williamson Durley on the matter of whether or not it was right to have cast a vote for the Whig Henry Clay in his presidential bid against James Polk (this account comes courtesy of Ronald C. White, Jr.’s excellent new biography A. Lincoln). Durley thought not; religious principles, Durley argued, forbade him and other champions of abolition from voting for Clay, a slaveholder who also opposed the expansion of slavery.

Using biblical imagery, Lincoln said of Henry Clay, “By the fruit the tree is to be known. An evil tree can not bring forth good fruit. If the fruit of electing Mr. Clay would have been to prevent the extension of slavery, could the act of electing have been evil?”

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