If the case is devoid of merit, the loser does pay in Federal Court - it is called Rule 11, Federal Rules Civil Procedure, I believe.
I was recently involved in a case where a pro se plaintiff (and a lawyer to boot!) was hit for $6500 in Rule 11 sanctions. That was, however, only half of defendant's out of pocket lawyer expense. Nothing awarded for defendant's time and bother. Defendant is contemplated suing the out of control lawyer for malicious prosecution. Oh yeah, out of control lawyer is of course appealing grant of Rule 11 sanctions. Deal could end up costing defendant a bundle, while out of control lawyer pays nothing for his continued frivolous filings.
Grant of Rule 11 sanctions is entirely discretionary on part of judge, both as to whether they are granted and in what amount. So it's not really "loser pays." Unfortunately.