Washington ? Fidel Castro’s crackdown on dissidents has taken momentum away from what had been a growing, bipartisan effort in Congress to ease four-decade-old U.S. sanctions.

Embargo opponents will continue to seek changes on grounds that Americans and ordinary Cubans are being punished, not Castro. Most admit, however, that prospects are dim.

Even before the crackdown, the likelihood was small that sanctions would be eased. President Bush strongly supports the embargo and has threatened to veto any bill to weaken it.

In growing numbers, however, free-trade Republicans, mostly from farm states, have joined Democrats in declaring the embargo a failure. They point out it has not forced Castro from power — its goal — but has denied Americans the freedom to do business or travel in Cuba.