In other words, if you could lay them out on the slab and jolt them with electricity until both their bodies and political careers became zombified, what parties do you believe they would feel more at home in today? I understand that this is purely speculative, and hence pretty well vague and subjective, but the mood struck me to post it all the same.
I've chosen to end the question at Franklin Roosevelt because the modern political alignment largely began with him and there'd likely not be as much difference. Naturally you must assume that, while their temperaments and ideals carry over, they have been updated for centuries of development, or you may have some unpleasantness in making your list.
My thoughts:
George Washington - a Republican-leaning Independent with a strong nationalist streak who may, however, not be altogether sympathetic to the more radically
laissez-faire tendencies of the modern Republicans.
John Adams - when Teabaggers and their kind complain about elitist "latte liberals", this is the prototype of the cause of their complains. Adams was very fond of Hamiltonian statist economics, though he may be Liebermanesque in his foreign policy and security views.
Thomas Jefferson - I can't see Jefferson feeling too at home in a Republican Party dominated by religious conservatives, and yet the thought of him being a modern Democrat is ridiculous.
James Madison - I perceive Madison as a moderate Republican, relatively hawkish on foreign affairs but friendly to civil libertarianism. He would have been of a sort to vote for McCain in the 2000 GOP primaries and against him in the one national election he actually participated in, I feel.
James Monroe - Monroe would in my view be a Paulite today, given his quarrels with Congress over domestic improvements and his support for American neutrality in the wake of the Napoleonic wars. I could, however, be mistaken on this.
John Quincy Adams - a quintessential liberal Democrat, through-and-through.
Andrew Jackson - I had great difficulty in deciding this one, simply because almost no Party presently existing actually represents anything close to what Jackson stood for while he was alive. The Republicans will try to claim descent from his ideals by virtue of being opposed to centralized banking and in favor of a strong national defense, yet Jackson's positions would have been on the
left of a hypothetical left-right spectrum adjusted for the political and economic environment of the time. All the same, Jackson would certainly not be a Democrat as we know them today, and he was far too hawkish to ever have been a libertarian. Ultimately I think he would be almost the image of a modern swing voter.
Martin van Buren - van Buren, as a political party boss of New York City and opponent of slavery, was relatively liberal in his day, and would surely be so in ours as well.
William Henry Harrison - Harrison's closest modern equivalent might be someone along the lines of Wesley Clark; Harrison was a Whig, and so favored the Whig programme of government intervention into the economy, and so I doubt seriously he'd be a Republican despite his former military career.
John Tyler - of the first ten Presidents, this is the one of which I am most sure. Despite his ostensible membership in the Whig Party, Tyler was the chiefmost proponent of the Democratic-Republican economic philosophy in his time and would be a strong southern conservative today.
James Polk - another no-brainer. If his term as President would be any indication whatsoever of his present sympathies, Polk would be a national defense oriented Republican.
Zachary Taylor - Taylor is problematic in ways similar to Jackson and Harrison, except in his case the problem rests in the fact that General Taylor was essentially a non-political man who took political office only at the behest of his friends. I wouldn't be surprised if Taylor didn't even vote were he alive today.
Millard Fillmore - I rank Fillmore as a Republican mostly on the basis of his post-Presidential activities as the candidate of the Know-Nothings in the election of 1856. I can easily see President Fillmore as being active in the nativist contingent of the Tea Party.
Franklin Pierce - the posterboy for the Northern 'doughface', Pierce's Dixie sympathies would likely not have changed in the one hundred and forty-two years since his death.
James Buchanan - for some reason unbeknown to me, reading about Buchanan's character reminds me strongly of fellow Pennsylvanian Democrats Ed Rendell and Bob Casey, and not just because of their home state. I get the intuition that Buchanan may have been a populist-oriented Democrat today had he survived into our era.
Abraham Lincoln - this will doubtless be the single most controversial decision I make in this thread, and I am more than prepared to justify it. If anyone wishes to dispute my reasoning for it, I leave this space open.
Andrew Johnson - largely self-explanatory.
Ulysses S. Grant - Grant was an economic corporatist then, and I doubt that would change very much in the interval between his era and ours. I suggest that Grant would be a moderate on social and foreign policy issues today, but quite 'conservative' on economics.
Rutherford Hayes - Hayes was probably the first President to display what we would today regard as 'progressive' sensibilities in a modern context, championing greater government involvement in education and civil rights. This must be tempered, however, by the understanding of
his use of Federal troops as strikebreakers in the Great Railroad Strike of 1877 and his restoration of the gold standard and retirement of the greenback. Hayes is very difficult to peg politically - a problem that plagues many Reconstruction-era Presidents - and so I place him as an independent as a matter of convenience.
James Garfield - Garfield's support of the Chinese Exclusion Act and opposition to the bureaucracy outs him as a modern Republican, though, I'd argue, a moderate one.
Chester Alan Arthur - this pick may prove controversial as well. Chet was reared in the civil service of the State of New York, a position that today would immediately incline one towards the Democratic Party. Moreover, Arthur initially vetoes the Chinese Exclusion Act, which, if framed in modern terms, would not endear him to Teabaggers and other nativists. I'd regard Arthur as a moderate Democrat, likely friendly to the DLC.
Grover Cleveland - everything he stood for as a Democrat then the Republicans stand for today.
Benjamin Harrison - high tariffs, high spending and the Federal Elections Bill mark Harrison out as a liberal.
William McKinley - McKinley would likely be more at home in today's Republican Party than he ever was in the GOP of his own time. He would likely be enthused at a Party which had largely abandoned the protective tariff and had accepted a far more assertive foreign policy than the Republicans of his day would ever have happily embraced.
Theodore Roosevelt - I think Teddy could set aside the rivalry between Oyster Bay and Hyde Park to support the accomplishments of his cousin. Aside from his militarism, Theo. Roosevelt shares almost nothing with his current heirs.
William Howard Taft - Taft's reputation for conservatism is (mostly) overrated. What Taft was as President was a placeholder, and he knew it; I can't see him bucking his personal feelings for party loyalty today.
Thomas Woodrow Wilson - along with Lincoln, this will likely be the most controversial of my picks. Yes, I'm well aware that Wilson inaugurated the Federal Reserve, the institution which Republicans are united together behind their loathing of. Yes, I'm aware that Wilson has been popularly mythologized as a 'progressive'. What I'm also aware of is that Wilson was a late convert to 'progressivism', having been
quite conservative in his tenure as President of Princeton University. I'd also suggest that his record as a foreign policy hawk and social conservatism would today outweigh his relative economic liberalism, as well as his southern sympathies.
Warren Harding - Harding would be a member of whatever Party would promote him further.
Calvin Coolidge - Coolidge would
probably be roughly analogous to someone like Gary Johnson, sympathetic to the activities of Ron Paul and his supporters while skeptical of the extremism of some of them.
Herbert Hoover - Hoover, like Taft, is one President whose conservatism is hugely overrated by individuals on both sides of the schism. Hoover was basically a 'progressive' of the Progressive Era - not a New Dealer by any means, he was nevertheless friendly of increased government intervention in the name of social justice. The man who campaigned on "a chicken in every pot" would probably have switched over to the Democrats during the 1980s.
Franklin Roosevelt - and how!
I don't expect anyone to follow my insanity of typing out lengthy explanations, but I'd be more than happy to hear your thoughts or suggestions all the same.