The news of a sweeping crackdown on illegal immigration Friday was delivered by Bush administration officials with a verbal finger wag, a warning carried out after Congress’ failure this summer to pass legislation that would have also included more lenient reforms.

Starting as early as next month, employers would face tougher sanctions for hiring illegal workers, federal contractors would have to use special software to confirm employee identities and plans for beefing up the U.S.-Mexico border with more fencing and Border Patrol officers would kick into gear – the best measures available under existing immigration law, officials said during a Washington news conference.

As conservatives gave cautious praise to the plans while unions, business groups and immigrant advocates predicted massive layoffs and other heartaches, both sides wondered whether the vise on the nation’s estimated 12 million illegal immigrants is intentionally being tightened to make more friendly measures easier to pass when Congress returns from its summer recess.

“If they’re trying to make another effort at amnesty in the fall, then this is a pretty smart thing they’re doing,” said Roy Beck, executive director of NumbersUSA, a Virginia-based organization that helped engineer a fierce grass-roots campaign in June to defeat a bipartisan Senate bill that would have offered legalization to undocumented immigrants.

Officials put the burden on Congress for any negative effects produced by some two dozen provisions laid out Friday.

“Our hope is that key elements of the Senate bill will see the light of day some day, but until Congress chooses to act, we are going to be taking some energetic steps of our own,” Homeland Security Secretary Michael Chertoff said.