Roll Call offers this breaking news report. A snippet:

Earlier Tuesday, a senior GOP aide said that Republican leaders expected the measure to pass. “It will be a party-line vote — and close and tough — but it will make it across the finish line,” the aide said. “It’s definitely one of the most important things we can do for our members this year.”
But Tuesday evening, another senior GOP aide said that Rep. Mike Pence (R-Ind.), author of a competing measure, will likely oppose the bill despite vigorous support from the Republican leadership.
Pence’s decision came after the House Rules Committee voted to block any floor amendments when lawmakers take it up Wednesday. He had wanted to propose swapping the measure under consideration for one he coauthored with Rep. Albert Wynn (D-Md.). He also wanted to offer a provision that would carve out contributions to political parties from caps on total giving placed on donors.

Bob Bauer offers more on the nuts and blots of the House vote:

The House Rules Committee yesterday sent a 527 bill to the floor. It was an entirely Republican affair: a closed rule, allowing for one hour of debate, and the core bill, HR 513, was changed only to add a Republican-favored provision repealing party spending (“coordinated expenditure”) limits. The leading reform organizations have decided to support this bill. Democrats will overwhelming oppose it, and it appears, as of this morning, that they will be joined by some Republicans, such as Republican Study Conference Chairman Mike Pence, who reject the sudden enthusiasm for regulation found in the Republican leadership.

Here and here are press releases from reform groups. Here is a National Review editorial against the bill, and that magazine reproduces this letter from conservative activists opposing the bill. Here is a Washington Post editorial supporting the House legislation. The Hill offers 527 Bill Splits Republicans. The Roll Call report notes: “Even if it passes the House, the bill faces long odds in the Senate, where Democratic leaders have pledged to defeat it.”