Which previous Republican presidency was Bush II most like?

[President Punxsutawney Phil]

Tentatively, I would postulate Grant.
Reasons:
1) business-related scandals (Enron vs Credit Mobilier)
2) "don't change the horse in midstream" style re-election campaigns
3) allegations of insiders taking advantage of a big-spending GOP administration
4) unpopular moral stances by some in their party (intelligent design and stem cells vs prohibition)
5) a bad midterm driven by the aforementioned things (2006 vs 1874)

Differences:
1) Grant led a party with a far stronger popular base, allowing it to win after he had served two terms
2) both were connected in some way towards a controversial, contested election, but 2000 came before Bush's tenure, and 1876 came after two terms of Grant
3) Bush obviously lost black voters, while Grant obviously won them

[TheElectoralBoobyPrize]

Kinda like Nixon in that he was relatively popular in his first term and very unpopular in his second. First terms in both cases were dominated by foreign policy/national security issues. Both left recessions in their second terms to their successor. Democrats won the WH and big majorities in Congress after both presidencies, but in both cases it was more a rejection of the unpopular Republican president than a mandate for another New Deal/Great Society.

[Vice President Christian Man]

While he was firmly in the Eisenhower/Nixon camp although I’d say Gerald Ford was the most similar in terms of personal beliefs.

[Brother Jonathan]

It seems that any comparison would have to include a major foreign policy event comparable to Iraq, and in that sense, I am not sure which previous Republican comes closest. If we include Democrats, then of course LBJ seems natural, but for Republicans, I am not sure. Maybe McKinley, though Nixon works well as noted above.

[Southern Senator North Carolina Yankee]

McKinley and Grant are great answers. I tend to lean more towards Grant in terms of events that played out.

Tentatively, I would postulate Grant.
Reasons:
1) business-related scandals (Enron vs Credit Mobilier)
2) "don't change the horse in midstream" style re-election campaigns
3) allegations of insiders taking advantage of a big-spending GOP administration
4) unpopular moral stances by some in their party (intelligent design and stem cells vs prohibition)
5) a bad midterm driven by the aforementioned things (2006 vs 1874)

Differences:
1) Grant led a party with a far stronger popular base, allowing it to win after he had served two terms
2) both were connected in some way towards a controversial, contested election, but 2000 came before Bush's tenure, and 1876 came after two terms of Grant
3) Bush obviously lost black voters, while Grant obviously won them

You missed two massively important similarities
6) Economic Crash (2007/2008 - 1873/1874)
7) Increasingly unpopular and yet arguably successful counter insurgencies (Late Reconstruction Period vs Post Surge Iraq)

[dw93]

On actual Economic and Social policy, Reagan. If we're including Presidents that came after, in terms of appealing/pandering to the least educated of the electorate and his complete disregard to international institutions he was very similar to Trump.

[NewYorkExpress]

He's probably closest to some combination of Eisenhower and Reagan, honestly. Both relied heavily on their advisors, both had strong beliefs (for Eisenhower and arguably Bush it was Foreign Policy, for Reagan it was largely social policy...except for dealing with the Soviet Union), and both were able to attract the brightest minds in the party at the time, much as Bush did, to serve in their administration.