Fine.
Were the Democrats forced to write unconstitutional mandates into their bills because the GOP had done it?
It just goes to show that no one seriously thinks the mandate is unconstitutional. If Republicans really thought it was unconstitutional, they wouldn't have been pushing it as an alternative for the Clinton plan in 1993, and they wouldn't be pushing it for Medicare (Ryan plan) and Social Security (various privatization schemes) today.
Uh, no it doesn't. The fact that a bill was introduced with a few cosponsors, Democrats among them, and got nowhere in the Senate, and never made it into the House, actually indicates the exact opposite. No one wanted to push a bill that was clearly unconstitutional.
But it won't be the first time you're completely wrong. In the last 30 minutes.