The political solution is 30 year term limits for Senate and House (5 terms and 15 terms respectively). The current system lack of term limits incentivizes inaction
Term limits for elective office are fake, nonworking solution to problems caused by a broken electoral system; the solution is to fix the electoral system, not to impose term limits (which solve nothing.)
Term limits make the problem worse; the main fix is to abandon strict single-member-district first-past-the-post for a more proportional system for legislative elections (for Presidential elections the problem is harder, both because there is no good, easy fix for an inherently single-winner election and because almost any meaningful change will require a Constitutional amendment which is quite difficult even if you can nail down what to do.)
For the House, using a multimember ranked ballots system like Single Transferrable Vote in districts capped at a size of 5 members in states with more than one rep would work tolerably well (especially if combined with increasing the total number of seats beyond the currently-legislated fixed 435.) This does all of support more parties, reduce or eliminate [depending on the exact method chosen] spoiler effects for voting first choice for parties that don't win seats reducing the need for tactical voting, reduce incumbent protection without removing voter choice [because parties are encouraged to run more candidates than they are likely to win], and produce a body that better represents the preferences of the electorate.
The Senate is more complicated because of the 1/3 per class rule, but it can be made slightly better (in order from smallest to largest changes), by:
1. Adopting a single-winner ranked choice method instead of first-past-the-post for Senate elections.
2. Increasing the size of the Senate to three seats per state (electing one Senator from each stare in each of the three two-year classes), combined with #1.
3. Increase the size of the Senate to six (2/state/class) or nine (3/state/class), using a ranked ballots multiwinner proportional system like STV for elections. (3/state/class keeps the majority a significant threshold.
Because of the Constitutional manner of apportioning electors, increasing the size of the House makes Presidential election voting power more equal by population while increasing the size of the Senate makes it less; for this reason, if doing the fixes for Congress discussed above, I would favor not increasing the size of the Senate by a greater multiple than thet of the house, so three per state in the Senate would go with at least a 50% increase in the size of the House, 2/state/class would go with at least tripling the House, 3/class/state would go with at least a 4.5× on the size of the House.
All are very-sound ideas. Regrettably, they'd be tough to explain to the voters — and the vested interests would oppose fiercely.
A good start might be to just triple the size of the House to approximately match the Repr.-to-population ratio when the present 435 number was legislated.
