The political consequences of the split within the AFL-CIO began to reverberate nationwide Tuesday, with Democrats fretting that it will dilute the importance of labor endorsements while Republicans looked for opportunities to make inroads.

Civil rights leader and two-time Democratic presidential candidate Jesse L. Jackson pleaded with the warring forces to end their fight. "We must turn to each other, not on each other," Jackson told 800 delegates to the AFL-CIO convention here. He warned against leaving "so much blood on the field that you cannot compete" against "anti-civil-rights, anti-labor-rights Republicans."

Democratic strategists and union operatives noted that the split will change the dynamics of presidential and state elections. Presidential candidates will now seek endorsements from two separate and competing labor groups, the AFL-CIO and the newly formed Change to Win Coalition, they noted.

"It's going to be like figuring out who to stay friends with after a divorce," one Democratic presidential operative said. In addition, he and others noted, there will be strong incentives for the two wings of labor to pick different candidates as each tries to outdo the other.

Republican operatives are watching the splintering of the AFL-CIO carefully to see if the divisions offer opportunities to gain a beachhead in labor. "This cuts the legs out from one of their main GOTV [get-out-the-vote] groups," a Republican Party official said with undisguised pleasure.

One of the unions leaving the federation, the 1.8 million-member Service Employees International Union, broke ranks last year to give the Republican Governors Association $575,000, the RGA's single largest contribution. The other defecting union, the International Brotherhood of Teamsters with 1.4 million members, has a long history of supporting Republican presidential candidates.

While the GOP is eagerly watching the internal labor battles, conservative groups are announcing plans to step in to try to further weaken the union movement. The National Right to Work Legal Defense Foundation announced plans to raise $2 million for "free legal assistance" to workers seeking to end their union membership and to stop paying dues.

Details of the damage inflicted on the AFL-CIO by the pullout of Andrew L. Stern's SEIU and James P. Hoffa's Teamsters, with a combined 3.2 million members and $18 million in federation dues, were fleshed out at an occasionally testy briefing at midday Tuesday.

AFL-CIO political director Karen Ackerman said the federation will now be barred by law from mobilizing Teamster and SEIU members for elections and for lobbying to pass legislation.

In addition, the bitterness that has already begun to surface in the wake of the Teamster-SEIU defection is, according to many on both sides of the fight, almost sure to escalate into open warfare when such unions as the American Federation of State, County and Municipal Employees and SEIU compete to organize such prime union targets as home health-care workers without the AFL-CIO as a referee.

"It's not going to be pleasant to watch," said Gerald W. McEntee, president of AFSCME, noting that such battles will divert cash, energy and resources away from politics.

The 2002 McCain-Feingold campaign finance law severely limits the amount unions can give to national political parties and federal candidates. Organized labor does, however, remain a key source of cash and manpower at the state and local level, especially in areas where contribution limits are high or absent altogether.

In 2004, labor remained a major financial player at the federal level by providing millions of dollars to the pro-Democratic but technically independent "527" organizations that sprang up to circumvent the McCain-Feingold law.

At the press briefing, AFL-CIO Secretary-Treasurer Richard L. Trumpka said the federation, which has a $120 million budget, is considering a dues increase to defray the losses in state federations and local central labor councils. These organizations play key roles in elections of all kinds, and they apply pressure on politicians when individual unions are seeking to organize local workers or to ensure that contractors pay union-level wages.

The Teamsters and the SEIU may soon be followed by the United Food and Commercial Workers and Unite Here, the union of hotel, restaurant and garment workers, which together have about 1.6 million members and pay more than $10 million in dues to the AFL-CIO.