I was directing my comments to the situation that exists today and while tampering with the electoral system to benefit both parties has been a bipartisan effort (look how Democrats/Republicans shut out third parties via FPTP/Top-two runoffs/high filing fees or signature requirements/etc), Republicans have certainly loved pushing measures that making voting and governing harder than necessary (supermajority requirements, unlimited campaign spending, restrictive voting time/registration periods, etc).
Neither of them is innocent, but one is worse than the other. All the more reason to strip them of the ability to tamper with it.
I wouldn't say the GOP is worse. If Democrats had the power, they'd be doing the same thing. However, the people put the GOP in charge.